Climate change and the textile industry

15 10 2014

Time sure flies doesn’t it?  I’ve been promising to reiterate the effects the textile industry has on climate change, so I’m re-posting a blog post we published in 2013:

In considering fabric for your sofa, let’s be altruistic and look at the impact textile production has on global climate change. (I only use the term altruistic because many of us don’t equate climate change with our own lives, though there have been several interesting studies of just how the changes will impact us directly,like the one in USA Today that explains that wet regions will be wetter, causing flash flooding; dry regions will get drier, resulting in drought. And … a heat wave that used to occur once every 100 years now happens every five years (1)).

Although most of the current focus on lightening our carbon footprint revolves around transportation and heating issues, the modest little fabric all around you turns out to be from an industry with a gigantic carbon footprint. The textile industry, according to the U.S. Energy Information Administration, is the 5th largest contributor to CO2 emissions in the United States, after primary metals, nonmetallic mineral products, petroleum and chemicals.[2] And the U.S. textile industry is small potatoes when compared with some other countries I could mention.

The textile industry is huge, and it is a huge producer of greenhouse gasses (GHG’s). Today’s textile industry is one of the largest sources of greenhouse gasses  on Earth, due to this huge size.[3] In 2008, annual global textile production was estimated at 60 billion kilograms (KG) of fabric. The estimated energy and water needed to produce that amount of fabric boggles the mind:

  • 1,074 billion kWh of electricity or 132 million metric tons of coal and
  • between 6 – 9 trillion liters of water[4]

Fabrics are the elephant in the room. They’re all around us but no one is thinking about them. We simply overlook fabrics, maybe because they are almost always used as a component in a final product that seems rather innocuous: sheets, blankets, sofas, curtains, and of course clothing. Textiles, including clothing, accounted for about one ton of the 19.8 tons of total CO2 emissions produced by each person in the U.S. in 2006. [5] By contrast, a person in Haiti produced a total of only 0.21 tons of total carbon emissions in 2006.[6]
Your textile choices do make a difference, so it’s vitally important to look beyond thread counts, color and abrasion results.
How do you evaluate the carbon footprint in any fabric? Look at the “embodied energy’ in the fabric – that is, all of the energy used at each step of the process needed to create that fabric. Not an easy thing to do! To estimate the embodied energy in any fabric it’s necessary to add the energy required in two separate fabric production steps:

  1. Find out what the fabric is made from, because the type of fiber tells you a lot about the energy needed to make the fibers used in the yarn. The carbon footprint of various fibers varies a lot, so start with the energy required to produce the fiber.
  2. Next, add the energy used to weave those yarns into fabric. Once any material becomes a “yarn” or “filament”, the amount of energy and conversion process to weave that yarn into a textile is pretty consistent, whether the yarn is wool, cotton, or synthetic.[7)

Let’s look at #1 first: the energy needed to make the fibers and create the yarn. For ease of comparison we’ll divide the fiber types into “natural” (from plants, animals and less commonly, minerals) and “synthetic” (man made):

For natural fibers you must look at field preparation, planting and field operations (mechanized irrigation, weed control, pest control and fertilizers (manure vs. synthetic chemicals)), harvesting and yields. Synthetic fertilizer use is a major component of the high cost of conventional agriculture: making just one ton of nitrogen fertilizer emits nearly 7 tons of CO2 equivalent greenhouse gases.
For synthetics, a crucial fact is that the fibers are made from fossil fuels. Very high amounts of energy are used in extracting the oil from the ground as well as in the production of the polymers.
A study done by the Stockholm Environment Institute on behalf of the BioRegional Development Group concludes that the energy used (and therefore the CO2 emitted) to create 1 ton of spun fiber is much higher for synthetics than for hemp or cotton:

KG of CO2 emissions per ton of spun fiber:
crop cultivation fiber production TOTAL
polyester USA 0 9.52 9.52
cotton, conventional, USA 4.2 1.7 5.9
hemp, conventional 1.9 2.15 4.05
cotton, organic, India 2 1.8 3.8
cotton, organic, USA 0.9 1.45 2.35

 

The table above only gives results for polyester; other synthetics have more of an impact: acrylic is 30% more energy intensive in its production than polyester [8] and nylon is even higher than that.
Not only is the quantity of GHG emissions of concern regarding synthetics, so too are the kinds of gasses produced during production of synthetic fibers. Nylon, for example, creates emissions of N2O, which is 300 times more damaging than CO2 [9] and which, because of its long life (120 years) can reach the upper atmosphere and deplete the layer of stratospheric ozone, which is an important filter of UV radiation. In fact, during the 1990s, N2O emissions from a single nylon plant in the UK were thought to have a global warming impact equivalent to more than 3% of the UK’s entire CO2 emissions.[10] A study done for the New Zealand Merino Wool Association shows how much less total energy is required for the production of natural fibers than synthetics:

 

Embodied Energy used in production of various fibers:
Energy use in MJ per KG of fiber:
flax fibre (MAT) 10
cotton 55
wool 63
Viscose 100
Polypropylene 115
Polyester 125
acrylic 175
Nylon 250
SOURCE: “LCA: New Zealand Merino Wool Total Energy Use”, Barber and Pellow, http://www.tech.plym.ac.uk/sme/mats324/mats324A9%20NFETE.htm

Natural fibers, in addition to having a smaller carbon footprint in the production of the spun fiber, have many additional benefits:

  • being able to be degraded by micro-organisms and composted (improving soil structure); in this way the fixed CO2 in the fiber will be released and the cycle closed. Synthetics do not decompose: in landfills they release heavy metals and other additives into soil and groundwater. Recycling requires costly separation, while incineration produces pollutants – in the case of high density polyethylene, 3 tons of CO2 emissions are produced for ever 1 ton of material burnt.[11] Left in the environment, synthetic fibers contribute, for example, to the estimated 640,000 tons of abandoned fishing nets in the world’s oceans.
  • sequestering carbon. Sequestering carbon is the process through which CO2 from the atmosphere is absorbed by plants through photosynthesis and stored as carbon in biomass (leaves, stems, branches, roots, etc.) and soils. Jute, for example, absorbs 2.4 tons of carbon per ton of dry fiber.[12]

Substituting organic fibers for conventionally grown fibers is not just a little better – but lots better in all respects:

  • uses less energy for production, emits fewer greenhouse gases and supports organic farming (which has myriad environmental, social and health benefits).  A study published by Innovations Agronomiques (2009) found that 43% fewer GHGs are emitted per unit area under organic agriculture than under conventional agriculture.[13] A study done by Dr. David Pimentel of Cornell University found that organic farming systems used just 63% of the energy required by conventional farming systems, largely because of the massive amounts of energy requirements needed to synthesize nitrogen fertilizers. Further it was found in controlled long term trials that organic farming adds between 100-400kg of carbon per hectare to the soil each year, compared to non-organic farming. When this stored carbon is included in the carbon footprint, it reduces the total GHG even further.[14] The key lies in the handling of organic matter (OM): because soil organic matter is primarily carbon, increases in soil OM levels will be directly correlated with carbon sequestration. While conventional farming typically depletes soil OM, organic farming builds it through the use of composted animal manures and cover crops

Taking it one step further beyond the energy inputs we’re looking at, which help to mitigate climate change, organic farming helps to ensure other environmental and social goals:

  • eliminates the use of synthetic fertilizers, pesticides and genetically modified organisims (GMOs) which is an improvement in human health and agrobiodiversity
  • conserves water (making the soil more friable so rainwater is absorbed better – lessening irrigation requirements and erosion)
  • ensures sustained biodiversity
  • and compared to forests, agricultural soils may be a more secure sink for atmospheric carbon, since they are not vulnerable to logging and wildfire.

Organic agriculture is an undervalued and underestimated climate change tool that could be one of the most powerful strategies in the fight against global warming, according to Paul Hepperly, Rodale Institute Research Manager. The Rodale Institute Farming Systems Trial (FST) soil carbon data (which covers 30 years) provides convincing evidence that improved global terrestrial stewardship–specifically including regenerative organic agricultural practices–can be the most effective currently available strategy for mitigating CO2 emissions.

At the fiber level it is clear that synthetics have a much bigger footprint than does any natural fiber, including wool or conventionally produced cotton. So in terms of the carbon footprint at the fiber level, any natural fiber beats any synthetic – at this point in time. Best of all is an organic natural fiber.
And next let’s look at #2, the energy needed to weave those yarns into fabric.
There is no dramatic difference in the amount of energy needed to weave fibers into fabric depending on fiber type.[15] The processing is generally the same whether the fiber is nylon, cotton, hemp, wool or polyester: thermal energy required per meter of cloth is 4,500-5,500 Kcal and electrical energy required per meter of cloth is 0.45-0.55 kwh. [16] This translates into huge quantities of fossil fuels – both to create energy directly needed to power the mills, produce heat and steam, and power air conditioners, as well as indirectly to create the many chemicals used in production. In addition, the textile industry has one of the lowest efficiencies in energy utilization because it is largely antiquated.

#######
(1) http://www.usatoday.com/story/news/nation/2013/02/28/climate-change-remaking-america/1917169/
(2) Source: Energy Information Administration, Form EIA:848, “2002 Manufacturing Energy Consumption Survey,” Form EIA-810, “Monthly Refinery Report” (for 2002) and Documentatioin for Emissions of Greenhouse Gases in the United States 2003 (May 2005). http://www.eia.doe.gov/emeu/aer/txt/ptb1204.html
(3) Dev, Vivek, “Carbon Footprint of Textiles”, April 3, 2009, http://www.domain-b.com/environment/20090403_carbon_footprint.html
(4) Rupp, Jurg, “Ecology and Economy in Textile Finishing”, Textile World, Nov/Dec 2008
(5) Rose, Coral, “CO2 Comes Out of the Closet”, GreenBiz.com, September 24, 2007
(6) U.S. Energy Information Administration, “International Energy Annual 2006”, posted Dec 8, 2008.
(7) Many discussions of energy used to produce fabrics or final products made from fabrics (such as clothing) take the “use” phase of the article into consideration when evaluating the carbon footprint. The argument goes that laundering the blouse (or whatever) adds considerably to the final energy tally for natural fibers, while synthetics don’t need as much water to wash nor as many launderings. We do not take this component into consideration because
. it applies only to clothing; even sheets aren’t washed as often as clothing while upholstery is seldom cleaned.
. is biodegradeable detergent used?
. Is the washing machine used a new low water machine? Is the water treated by a municipal facility?
. Synthetics begin to smell if not treated with antimicrobials, raising the energy score.
Indeed, it’s important to evaluate the sponsors of any published studies, because the studies done which evaluate the energy used to manufacture fabrics are often sponsored by organizations which might have an interest in the outcome. Additionally, the data varies quite a bit so we have adopted the values which seem to be agreed upon by most studies.
(8) Ibid.
(9) “Tesco carbon footprint study confirms organic farming is energy efficient, but excludes key climate benefit of organic farming, soil carbon”, Prism Webcast News, April 30, 2008, http://prismwebcastnews.com/2008/04/30/tesco-carbon-footprint-study-confirms-organic-farming%E2%80%99s-energy-efficiency-but-excludes-key-climate-benefit-of-organic-farming-%E2%80%93-soil-carbon/
(10) Fletcher, Kate, Sustainable Fashion and Textiles, Earthscan, 2008, Page 13
(11) “Why Natural Fibers”, FAO, 2009: http://www.naturalfibres2009.org/en/iynf/sustainable.html
(12) Ibid.
(13) Aubert, C. et al., (2009) Organic farming and climate change: major conclusions of the Clermont-Ferrand seminar (2008) [Agriculture biologique et changement climatique : principales conclusions du colloque de Clermont-Ferrand (2008)]. Carrefours de l’Innovation Agronomique 4. Online at
(14) International Trade Centre UNCTAD/WTO and Research Institute of Organic Agriculture (FiBL); Organic Farming and Climate Change; Geneva: ITC, 2007.
(15) 24th session of the FAO Committee on Commodity Problems IGG on Hard Fibers of the United Nations
(16) “Improving profits with energy-efficiency enhancements”, December 2008, Journal for Asia on Textile and Apparel, http://textile.2456.com/eng/epub/n_details.asp?epubiid=4&id=3296

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How to buy a quality sofa – part 4: synthetic fibers

3 10 2012

So from last week’s post, you  know that you want a durable, colorfast fabric that will be lovely to look at and wonderful to live with.  What’s the best choice?  I’m so glad you asked.

You have basically two choices in fibers:  natural (cotton, linen, wool, hemp, silk)  or synthetic (polyester, acrylic, nylon, etc.).  Many fabrics today are made from blends of natural and synthetic fibers – it has been said that most sheet sets sold in the U.S. are cotton/poly blends.

Natural fibres breathe, wicking moisture from the skin, providing even warmth and body temperature;  they are renewable, and decay at end of life.  On the other hand, synthetics do not breathe,  trapping body heat and perspiration; they are based on crude oil, definitely a non-renewable resource and they do not decompose at end of life, but rather remain in our landfills, leaching their toxic monomers into our groundwater.  They are, however, cheap and durable.

I like to think that even without the health issues involved I’d choose to live with natural fibers, since they work so well with humans!  The fibers themselves present no health issues and they’re comfortable.  But they simply don’t last as long as synthetics. But I have begun to see the durability of synthetics as their Dorian Grey aspect, in other words they last so long that they’ve become a huge problem.  By not decomposing, they just break into smaller and smaller particles which leach their toxic monomers into our groundwater.

The impact on health (ours the the planet’s) is an issue that’s often overlooked when discussing the merits of natural vs. synthetic.   And it’s a complex issue, so this week we’ll explore synthetic fibers, and next week we’ll look at natural fibers.

The most popular synthetic fiber in use today is polyester.

At this point, I think it would be good to have a basic primer on polyester production, and I’ve unabashedly lifted a great discussion from Marc Pehkonen and Lori Taylor, writing in their website diaperpin.com:

Basic polymer chemistry isn’t too complicated, but for most people the manufacture of the plastics that surround us is a mystery, which no doubt suits the chemical producers very well. A working knowledge of the principles involved here will make us more informed users.

Polyester is only one compound in a class of petroleum-derived substances known as polymers. Thus, polyester (in common with most polymers) begins its life in our time as crude oil. Crude oil is a cocktail of components that can be separated by industrial distillation. Gasoline is one of these components, and the precursors of polymers such as polyethylene are also present.

Polymers are made by chemically reacting a lot of little molecules together to make one long molecule, like a string of beads. The little molecules are called monomers and the long molecules are called polymers.

Like this:

O + O + O + . . . makes OOOOOOOOOOOOOOOO

Depending on which polymer is required, different monomers are chosen. Ethylene, the monomer for polyethylene, is obtained directly from the distillation of crude oil; other monomers have to be synthesized from more complex petroleum derivatives, and the path to these monomers can be several steps long. The path for polyester, which is made by reacting ethylene glycol and terephthalic acid, is shown below. Key properties of the intermediate materials are also shown.

The polymers themselves are theoretically quite unreactive and therefore not particularly harmful, but this is most certainly not true of the monomers. Chemical companies usually make a big deal of how stable and unreactive the polymers are, but that’s not what we should be interested in. We need to ask, what about the monomers? How unreactive are they?

We need to ask these questions because a small proportion of the monomer will never be converted into polymer. It just gets trapped in between the polymer chains, like peas in spaghetti. Over time this unreacted monomer can escape, either by off-gassing into the atmosphere if the initial monomers were volatile, or by dissolving into water if the monomers were soluble. Because these monomers are so toxic, it takes very small quantities to be harmful to humans, so it is important to know about the monomers before you put the polymers next to your skin or in your home. Since your skin is usually moist, any water-borne monomers will find an easy route into your body.

Polyester is the terminal product in a chain of very reactive and toxic precursors. Most are carcinogens; all are poisonous. And even if none of these chemicals remain entrapped in the final polyester structure (which they most likely do), the manufacturing process requires workers and our environment to be exposed to some or all of the chemicals shown in the flowchart above. There is no doubt that the manufacture of polyester is an environmental and public health burden that we would be better off without.

What does all of that mean in terms of our health?  Just by looking at one type of cancer, we can see how our lives are being changed by plastic use:

  • The connection between plastic and breast cancer was first discovered in 1987 at Tufts Medical School in Boston by research scientists Dr. Ana Soto and Dr. Carlos Sonnenschein. In the midst of their experiments on cancer cell growth, endocrine-disrupting chemicals leached from plastic test tubes into the researcher’s laboratory experiment, causing a rampant proliferation of breast cancer cells. Their findings were published in Environmental Health Perspectives (1991)[1].
  • Spanish researchers, Fatima and Nicolas Olea, tested metal food cans that were lined with plastic. The cans were also found to be leaching hormone disrupting chemicals in 50% of the cans tested. The levels of contamination were twenty-seven times more than the amount a Stanford team reported was enough to make breast cancer cells proliferate. Reportedly, 85% of the food cans in the United States are lined with plastic. The Oleas reported their findings in Environmental Health Perspectives (1995).[2]
  • Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic. [3]

These studies support claims that plastics are simply not good for us – prior to 1940, breast cancer was relatively rare; today it affects 1 in 11 women.  We’re not saying that plastics alone are responsible for this increase, but to think that they don’t contribute to it is, we think, willful denial.  After all, gravity existed before Newton’s father planted the apple tree and the world was just as round before Columbus was born.

Polyester fabric is soft, smooth, supple – yet still a plastic.  It contributes to our body burden in ways that we are just beginning to understand.  And because polyester is highly flammable, it is often treated with a flame retardant, increasing the toxic load.  So if you think that you’ve lived this long being exposed to these chemicals and haven’t had a problem, remember that the human body can only withstand so much toxic load – and that the endocrine disrupting chemicals which don’t seem to bother you may be affecting generations to come.

And then there is acrylic.  The key ingredient of acrylic fiber is acrylonitrile, (also called vinyl cyanide). It is a carcinogen (brain, lung and bowel cancers) and a mutagen, targeting the central nervous system.  According to the Centers for Disease Control and Prevention, acrylonitrile enters our bodies through skin absorption, as well as inhalation and ingestion.  So could the acrylic fibers in our acrylic fabrics be a contributing factor to these results?

Acrylic fibers are just not terrific to live with anyway.  Acrylic manufacturing involves highly toxic substances which require careful storage, handling, and disposal. The polymerization process can result in an explosion if not monitored properly. It also produces toxic fumes. Recent legislation requires that the polymerization process be carried out in a closed environment and that the fumes be cleaned, captured, or otherwise neutralized before discharge to the atmosphere.(4)

Acrylic is not easily recycled nor is it readily biodegradable. Some acrylic plastics are highly flammable and must be protected from sources of combustion.

Just in case you missed the recent report which was published in Occupational and Environmental Medicine [5], a Canadian study found that women who work with some common synthetic materials could treble their risk of developing breast cancer after menopause. The data included women working in textile factories which produce acrylic fabrics – those women have seven times the risk of developing breast cancer than the normal population, while those working with nylon fibers had double the risk.

What about nylon?  Well, in a nutshell, the production of nylon includes the precursors benzene (a known human carcinogen) and hydrogen cyanide gas (extremely poisonous); the manufacturing process releases VOCs, nitrogen oxides and ammonia.  And finally there is the addition of those organophosphate flame retardants and dyes.

[1] http://www.bu-eh.org/uploads/Main/Soto%20EDs%20as%20Carcinogens.pdf

[2] http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.95103608

[3] Sax, Leonard, “Polyethylene Terephthalate may Yield Endocrine Disruptors”,
Environmental Health Perspectives, April 2010, 118 (4): 445-448

(4) ) http://www.madehow.com/Volume-2/Acrylic-Plastic.html

(5) Occupational and Environmental Medicine 2010, 67:263-269 doi: 10.1136/oem.2009.049817 (abstract: http://oem.bmj.com/content/67/4/263.abstract) SEE ALSO: http://www.breastcancer.org/risk/new_research/20100401b.jsp AND http://www.medpagetoday.com/Oncology/BreastCancer/19321





Biopolymers and polylactic acid (PLA) – or rather, Ingeo

27 04 2011

Synthetic polymers have experienced almost exponential growth since 1950, and today about 5% of world oil production is used for that purpose.  In fact, we will need 25% or more of the current oil production for making polymers by the end of this century.

Some synthetic polymers are used to make fibers, and they have been around for a while:  rayon was discovered in 1924 and nylon in 1939.  But synthetic use really began to take off only since about 1953,  when polyester was discovered.  Qualities like durability and water resistance make synthetics highly desirable in many applications.  Today synthetics account for about half of all fiber usage.

This, despite the fact that synthetics are made from fossil fuel, and the contaminants from the manufacturing leach into our waterways and pollute the atmosphere, and the fact that they are not biodegradable and therefore don’t break down in landfills.  So recently there has been a spotlight on bio-plastics.

Bio plastics, or biopolymers –  in other words, synthetic plastics produced from biological sources –  are derived from cellulose. Cellulose is abundant – it’s said to make up half of all the organic carbon on the planet.   The most often-used biopolymers  include:

  • natural rubber (in use since the mid-1700s),
  • cellulosics (invented in the late-1800s),
  • and nylon 11 (polyamide – or PA 11) and 6–10 (polyamide 6/10) (mid-1900s).

A recent addition to the list is polylactic acid (PLA).  PLA is made from corn starch (in the United States), tapioca products (roots, chips or starch, mostly in Asia) or sugar cane (the rest of the world).[1]  You’ve probably heard about polylactic acid (PLA),  because Cargill, one of the largest agricultural firms on Earth, has invested heavily in it.  Cargill’s wholly owned subsidiary, NatureWorks, is the primary producer of PLA in the United States.  The brand name for NatureWorks PLA is Ingeo, which is made into a whole array of products, including fabrics.

The producers of PLA have touted the eco friendliness of PLA based on:

  1. the fact that it is made from annually renewable resources ,
  2.  that it will biodegrade in the environment all the way to carbon dioxide and water  –  at least in principle, and
  3. they also cite PLA’s lower carbon footprint.

Let’s take a look at these three claims.

Plant based biopolymers do come from renewable resources, but the feedstock used presents some interesting problems.  In the United States, corn is used to make the PLA. In the US, corn-based biopolymer producers have to compete with ethanol producers of government mandated gasoline blends, raising the cost and limiting availability for both. This problem will become worse in the future as the law requires a doubling of the percentage of ethanol used in motor fuel. Nearly a third of the US corn crop previously used for food was used to replace 5% of gasoline consumption in 2008.[2]

In a world where many people are starving, many say that it seems almost criminal to grow food crops, such as corn, to turn it into cloth. Agricultural lands are often cleared to make way for the growing of crops for the production of polymers. This leads to a continuous shrinking of the food producing lands of the world.  Lester Brown, president of the Earth Policy Institute, says, “already we’re converting 12% of the US grain harvest to ethanol (anticipated to rise to 23% by 2014). How much corn do we want to convert to nonfood uses?”[3]

In addition, most of the corn used by NatureWorks to make PLA is genetically modified, which raises serious ethical issues.

Other critics point to the steep environmental toll of industrially grown corn. The cultivation of corn uses more nitrogen fertilizer, more herbicides and more insecticides than any other U.S. crop; those practices contribute to soil erosion and water pollution when nitrogen runs off fields into streams and rivers.

PLA is said to decompose into carbon dioxide and water in a “controlled composting environment” in 90 days or less.  What’s that?  Not exactly your backyard compost heap!  It’s an industrial facility where microbes work at 140 degrees or more for 10 consecutive days.  In reality very few consumers have access to the sort of composting facilities needed to degrade PLA.  NatureWorks has identified 113 nationwide – some handle industrial food-processing waste or yard trimmings, others are college or prison operations .  Moreover, PLA in quantity can interfere with municipal compost operations because it breaks down into lactic acid, which makes the compost wetter and more acidic.

It looks like most PLA will end up in landfills, where there is no evidence it will break down any faster than PET.  Glenn Johnston, manager of global regulatory affairs for NatureWorks, says that a PLA container dumped into a landfill will last as long as a PET bottle.[4]

In fact, manufacturers have changed their stance: PLA is now defined as “compostable” instead of biodegradable, meaning more heat and moisture is needed to degrade PLA than is found in your typical backyard compost bin.

So far, biopolymer producers have had problems demonstrating that their materials have smaller carbon footprints than fossil fuel-derived polymers.   The energy inefficiencies of planting, growing, and transporting biological feedstocks mean more total energy is likely consumed to produce a unit of biopolymer than to make a unit of an oil or gas-based polymer.

However, Ramani Narayan of Michigan State University  found that “the results for the use of fossil energy resources and GHG emissions are more favorable for most bio based polymers than for oil based. As an exception, landfilling of biodegradable polymers can result in methane emissions (unless landfill gas is captured) which may make the system unattractive in terms of reducing greenhouse gas emissions.”[5]

Dr. Narayan recommended that, relative to their conventional counterparts, green polymers  should:

  • save at least 20 MJ (non-renewable) energy per kg of polymer,
  • avoid at least 1 kg CO2 per kg polymer and
  • reduce most other environmental impacts by at least 20%.

From this point of view, he says,  green plastics  can be defined in a broad and target-oriented manner.

But  carbon footprints may be an irrelevant measurement, because it has been established that plants grow more quickly and are more drought and heat resistant in a CO2 enriched atmosphere. Many studies have shown that worldwide food production has risen, possibly by as much as 40%, due to the increase in atmospheric CO2 levels. Therefore, it is both ironic  and a significant potential problem for biopolymer production if the increased CO2 emissions from human activity were rolled back, causing worldwide plant growth to decline.  This in turn would greatly increase the  competition for biological sources of food and fuel –  with biopolymers coming in last place.[6]

A further problem with biopolymers (except for future PE/PP made from sugar cane) is that  they require additional sorting at commercial recycling centers to avoid contaminating other material streams, and, although segregated collection helps, it is complex and increases costs.

In the final analysis, newer biopolymers don’t yet perform as well as oil based polymers, especially in terms of lower heat and moisture resistance, so the user might feel green but gets results that are less sustainable and more limited in use.  PLA remains a boutique polymer, and some see the best value proposition for biopolymers to be where their use is based on their unique properties, such as in medical and dental implants, sutures, timed released chemotherapy, etc. , because  PLA will slowly come apart in the body over time, so it can serve as a kind of scaffold for bone or tissue regrowth or for metered drug release.  But this is a small and specialized market.

But still, the potential and need for plastic alternatives has become acute:  The SPI Bioplastic Council anticipates that the biopolymer market will exceed $1 billion by 2012 – today it is half that.   Bioplastic remains “a sector that is not yet mature but will be growing fast in the coming years,” says Frederic Scheer , CEO of Cereplast and the so-called ‘Godfather of Bioplastics.’  It has not matured because of high production costs and the restricted capacity of biomass-based polymers.

But  according to The ETC Group, there are already concerted efforts, using biotechnology,  to shift global industrial production from a dependence on fossil fuels to biomass – not only for plastics but also for power, chemicals, and more.  It sounds good – until you read their report, which I’ll cover next week.


[2] Jones, Roger, “Economics, Sustainability, and the Public Perception of Biopolymers”, Society of Plastics Engineers, http://www.4spepro.org/pdf/000060/000060.pdf

[3] Royte, Elizabeth, “Corn Plastic to the Rescue”, Smithsonian,  August 2006

[4] Ibid.

[5] Narayan, Ramani, “Review and Analysis of Bio-based Product LCA’s”, Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI 48824

[6] D. B. Lobell and C. B. Field, Global scale climate-crop yield relationships and the impacts

of recent warming, Env. Res. Letters 2, pp. 1–7, 2007  AND

L. H. Ziska and J. A. Bunce, Predicting the impact of changing CO2 on crop yields:

some thoughts on food, New Phytologist 175, pp. 607–618, 2007.





Breast cancer and acrylic fibers

16 09 2010

Just in case you missed the recent report which was published in Occupational and Environmental Medicine [1], a Canadian study found that women who work with some common synthetic materials could treble their risk of developing breast cancer after menopause.  The data included  women working in textile factories which produce acrylic fabrics   –  those women have seven times the risk of developing breast cancer than the normal population, while those working with nylon fibers had double the risk.

I found it interesting that the researchers justified their findings because “synthetic fibers are typically treated with several chemicals, such as flame retardants from the organophosphate family, delustering agents, and dyes, some of which have estrogenic properties and may be carcinogenic.”

These are the same organophosphate flame retardants and dyes that are used across the textile spectrum, and which are found in most textiles that we surround ourselves with each day.

But also let’s look at the fibers themselves.  The key ingredient of acrylic fiber is acrylonitrile, (also called vinyl cyanide). It is a carcinogen (brain, lung and bowel cancers) and a mutagen, targeting the central nervous system.  According to the Centers for Disease Control and Prevention, acrylonitrile enters our bodies through skin absorption, as well as inhalation and ingestion.  So could the acrylic fibers in our acrylic fabrics be a contributing factor to these results?

Acrylic fibers are just not terrific to live with anyway.  Acrylic manufacturing involves highly toxic substances which require careful storage, handling, and disposal. The polymerization process can result in an explosion if not monitored properly. It also produces toxic fumes. Recent legislation requires that the polymerization process be carried out in a closed environment and that the fumes be cleaned, captured, or otherwise neutralized before discharge to the atmosphere.(2)

Acrylic is not easily recycled nor is it readily biodegradable. Some acrylic plastics are highly flammable and must be protected from sources of combustion.

What about nylon?  Well, in a nutshell, the production of nylon includes the precursors benzene (a known human carcinogen) and hydrogen cyanide gas (extremely poisonous); the manufacturing process releases VOCs, nitrogen oxides and ammonia.  And finally there is the addition of those organophosphate flame retardants and dyes.

Of course, there are the usual caveats about the study, and those commenting on it said further studies were needed since chance or undetected bias could have played a role in the findings. In addition, according to Reuters, “the scientists said more detailed studies focusing on certain chemicals were now needed to try to establish what role chemical exposure plays in the development of breast cancer.”  So this is yet another area in which more research needs to be done.  No surprise there.

But in the meantime, did you know that many popular fabrics are made of acrylic fibers?   One of the most popular is Sunbrella outdoor fabrics.     Sunbrella fabrics have been certified by GreenGuard Children and Schools because the chemicals used in acrylic production are bound in the polymer – in other words, they do not evaporate.   So Sunbrella fabrics do not contribute to poor air quality, (you won’t be breathing them in), but there is no guarantee that you won’t absorb them through your skin.  And you would be supporting the production of more acrylic, the production of which is not a pretty thing.

And what about backings on fabrics?  Many are made of acrylic.  Turn those fabric samples over and see if there is a plastic film on the back – it’s often made of acrylic.  Upholsterers like fabrics to be backed because it makes the process much easier and stabilizes the fibers.

So I don’t know about you, but I think I’ll avoid those synthetics for now – at least until we know where we stand.


[1] Occupational and Environmental Medicine 2010, 67:263-269 doi: 10.1136/oem.2009.049817  (abstract: http://oem.bmj.com/content/67/4/263.abstract)  SEE ALSO:  http://www.breastcancer.org/risk/new_research/20100401b.jsp AND http://www.medpagetoday.com/Oncology/BreastCancer/19321

(2)  http://www.madehow.com/Volume-2/Acrylic-Plastic.html