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Ramani Narayan, Michigan State University UNDERSTANDING BIODEGRADABILITY ROLE IN PLASTICULTURE MYTHS & REALITY Ramani Narayan University Distinguished.

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Presentation on theme: "Ramani Narayan, Michigan State University UNDERSTANDING BIODEGRADABILITY ROLE IN PLASTICULTURE MYTHS & REALITY Ramani Narayan University Distinguished."— Presentation transcript:

1 Ramani Narayan, Michigan State University UNDERSTANDING BIODEGRADABILITY ROLE IN PLASTICULTURE MYTHS & REALITY Ramani Narayan University Distinguished Professor MICHIGAN STATE UNIVERSITY If you use any of the slides/materials, please reference authorship and affiliation (Ramani Narayan, Michigan State University) – thank you Copyright Ramani Narayan & MATERIALS SCIENCE

2 Ramani Narayan, Michigan State University PLASTICULTURE TECHNOLOGY  plastic mulch is standard practice used in agriculture to control weeds, increase crop yield, and shorten time to harvest  contributes significantly to the economic viability of farmers  Disposal is an issue – contributes to cost, and impacts on the environment SOLUTION  DEGRADABILITY AND BIODEGRADABILITY  DEGRADABILITY

3 Ramani Narayan, Michigan State University The “VALUE PROPOSITION” FOR USING BIORESINS (BIOBASED AND OR BIODEGRADALBE) Using biodegradability as an end-of-life option to completely remove single use short life disposable plastics from the environmental compartment in a safe and efficacious manner via microbial assimilation Degradable, partial biodegradable not acceptable – serious health and environmental consequences Disposal environment (like composting, anaerobic digestor, marine Time to complete biodegradation Using bio/renewable feedstock (as opposed to petro/fossil feedstock: Reduces our carbon footprint and moves us to zero carbon or carbon neutral footprint Reduce CO 2 emissions --- global warming climate change Provides a positive environmental footprint/profile (document using LCA tools)

4 Ramani Narayan, Michigan State University TERMINOLOGY BIOBASED (RENEWABLE) Organic material containing in whole or part biogenic (biological sources) carbon Refers to using biomass or crop feedstock (New carbon) vs petroleum or fossil feedstock (Old carbon) Reducing carbon footprint BIODEGRADABILITY – END-OF-LIFE option functional property attribute to be designed and engineered into a biobased product when needed or necessary!! need to identify the (end-of-life)disposal system like composting, anaerobic digestion, marine, soil using microbes to completely utilize the carbon substrate and removing it from the environmental compartment Time to complete microbial utilization – no residue remaining BIOMATERIALS -- Biomedical applications Refers to: Any material (metal, plastic, ceramic) implanted in the body -- design and engineering considerations different; biodegradability considerations different

5 Ramani Narayan, Michigan State University TERMINOLOGY  Biobased plastics or products Organic material(s) containing in whole or part biogenic carbon -- carbon from contemporary (non-fossil) biological sources – NEW CARBON Organic material(s) – IUPAC terminology Material(s) containing carbon based compound(s) in which the carbon is attached to other carbon atom(s), hydrogen, oxygen, or other elements in a chain, ring, or three dimensional structure Thus, to be classified biobased or biomass based, or renewable, the material must be organic and contain biogenic carbon (from biological sources)

6 Ramani Narayan, Michigan State University Terminology (Contd) BIOBASED OR BIOMASS BASED OR RENEWABLLY SOURCED PLASTICS OR PRODUCTS NOT BIODEGRADABLE BIODEGRADABLE (Complete) Petro based not biobased PLASTICS OR PRODUCTS BIOBASED AND BIODEGRADABLE (complete!) PLASTICS OR PRODUCTS BIOPLASTICS IMPORTANT: Biodegradability MUST be defined/ constrained by: the disposal system – composting, anaerobic digestor Time – 180 days ; max 1 year Complete utilization of the substrate carbon by the microorganisms as measured by the evolved CO 2

7 Ramani Narayan, Michigan State University DESIGNING FOR BIODEGRADABILITY – WHEN, & WHY? Durable Products – BIOBASED [reduced carbon footprint] biodegradability is not required element for reasons of performance, safety and long product life alternate methods of disposal needs to be identified Example -- BIO polyurethanes for automotive and farm vehicles Example -- Biofiber composites for industrial and automotive applications Example – Biopolyethylene ethanol to ethylene to PE BIODEGRADABILITY – For single use, short-life (controlled-life time), disposable products [end-of-life option] Like packaging, disposable plastics, agricultural films, marine disposable Designed for disposal systems like composting, anaerobic digestion, marine and soil disposal BIOBASED is added positive attribute IMPORTANT -- Must define environment and time required to ensure complete removal from the environmental compartment otherwise serious environmental and human health consequences

8 Ramani Narayan, Michigan State University BIODEGRADABILITY -- END OF LIFE OPTIONS COMPOSTING FACILITY COMPOSTING FACILITY RECYCLING FACILITY RECYCLING FACILITY WASTE TO ENERGY FACILITY WASTE TO ENERGY FACILITY Biodegradable Plastics Biodegradable Plastics RECYCLED PRODUCTS LAND APPLICATION recycling polymeric carbon back to soil ENERGY INCINERABLE Anaerobic digestion facility Marine environment Paper-biopolymer composite Landfill X Unless managed for landfill gas recovery for energy BIOBASED PLASTICS

9 Standards in place for Biodegradability as end-of-life option (Integration of Biodegradable Materials with Disposal Infrasructures) Biodegradable Materials Biodegradable Materials COMPOSTING FACILITY COMPOSTING FACILITY LAND APPLICATION recycling polymeric carbon back to soil TEST METHOD ASTM D5338; ISO & 2 ISO16939 (disintegration) ASTM D6340 C-14 SPECIFICATIONS ASTM D6400; EN ISO ASTM D6868 – paper coatings Waste water treatment facility Waste water treatment facility ASTM D5271 ISO 14851/14852 Anaerobic digestion biogas energy plant ASTM D5511 ISO Soil Mulch film Agriculture appl Soil Mulch film Agriculture appl ASTM D 5988 Marine & fresh water ASTM D 6691,6692 D 7021 specification Ramani Narayan, Michigan State University,

10 Global Standards for Biodegradability ISO Specification for compostable plastic

11 Ramani Narayan, Michigan State University What is this all about? Myths and Green Washing – where is the data? Industry debates: What’s biodegradable? Plastics News October 6, 2006 Oxobiodegradation is a process by which polyolefins can be accelerated to break down into low molecular weight species. Through the action of microbes, the material is transformed into CO 2, water and biomass Have been used for many years in corn fields – no build of the films in the soil is evident, nor are there any issues with plant growth. Company claims that the material meets ASTM D5209, D5338 standards for biodegradability Products that conform to D6954 standard which allows for slower breakdown of materials wont get through

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15 “PERF GO GREEN Bags will completely break down in a landfill environment in months leaving no residue or harmful toxins and have a shelf life of 2 years.”

16 Ramani Narayan, Michigan State University Claims of biodegradability

17 Ramani Narayan, Michigan State University Claims of biodegradability

18 Basic Technology –All of the commodity plastic resins used in the world today will take hundreds of years or more to degrade naturally in the environment –Plastic products with our additives will biodegrade to become some of the soils’ organic components in a hundredth of that time or less Biodegrade

19 Conclusion Make all PE and PP products fully biodegradable No toxic residue Manufacture clear or in any color with no appreciable change in physical properties FDA compliant for use in applications with food contact Products can be marketed as “biodegradable” because they will biodegrade aerobically or anaerobically and without the need for additional reaction to heat, light or physical stress and therefore will biodegrade wherever there is other biodegradation occurring.

20 Ramani Narayan, Michigan State University, Quote from Industry website “The two main types are oxo-biodegradable and hydro-biodegradable. In both cases degradation begins with a chemical process (oxidation or hydrolysis), followed by a biological process. Both types emit CO2 as they degrade, but hydro biodegradable can also emit methane” The plastic does not just fragment, but is consumed by micro-organisms after the additive has reduced the molecular weight to sub 40,000 Daltons, and it is therefore "biodegradable." This process continues until the material has biodegraded to nothing more than CO2, water, humus, and trace elements. Oxo-biodegradable plastics Association Sept 08, 2008

21 Ramani Narayan, Michigan State University, The 50% Bio-Batch film did not degrade as completely or as quickly as the cellulose. At the end of the test, 19% of the film had degraded. The results of the aerobic degradation tests indicate that, in time, plastics produced using Bio-Batch pellets will biodegrade in aerobic conditions.

22 Ramani Narayan, Michigan State University, BIODEGRADABILITY CLAIMS  Chem. Commun., 2002, (23), – A hypothesis was developed, and successfully tested, to greatly increase the rates of biodegradation of polyolefins, by anchoring minute quantities of glucose, sucrose or lactose, onto functionalized polystyrene (polystyrene-co-maleic anhydride copolymer) and measuring their rates of biodegradation, which were found to be significantly improved  PRESS  Sugar turns plastics biodegradable. Bacteria make a meal of sweetened polythene and polystyrene. weight loss of only 2-12%, Only sugar is being assimilated, PE chain intact – Is this a genuine example of biodegradable plastic?

23 Ramani Narayan, Michigan State University WHAT IS THE VALUE PROPOSITION FOR BIODEGRADABILITY? End-of-life option for complete removal of the plastic product from the environmental compartment in a safe and efficacious manner – enter into the microbial food chain!!! Need to define disposal systems or environment like composting (compostable plastic), anaerobic digestor, soil, marine) Need to define TIME to complete biodegradation (90%+ of the carbon substrate should be completely assimilated by the microorganisms present in the disposal within a short time period (one year or less) Degradability, partial biodegradability, or will eventually biodegrade is not an option! – serious health and environmental consequences  ASTM D6400, D6868, D7021 (U.S. Govt procurement law, State of CA, San Francisco India, China, Korea)  EN European Packaging Directives  ISO (China, Korea, India)

24 Ramani Narayan, Michigan State University, Why Biodegradable Plastics? How does it work? Low-temperature electron micrograph of a cluster of E. coli bacteria, magnified 10,000 times. Each individual bacterium is oblong shape  Harness the power of microbes in soil to completely remove the carbon based plastics from the environment.  How?  By ensuing that it is completely consumed by the microorganisms (as its carbon food) for driving its life processes in a short and defined time frame and in the specified environment  the carbon product is taken inside the microbial cell and biologically oxidized to CO2 which releases energy that is utilized by the microorganism for its life processes – to multiply and grow and populate the soil for biological activity

25 Ramani Narayan, Michigan State University Microorganisms extract chemical energy for use in their life processes by the aerobic oxidation of glucose and other utilizable substrates – BIODEGRADBLE PLASTICS, food waste, paper, forest residues biological matter Glucose/C-bioplastic + 6 O 2 6 CO2 + 6 H2O;  G 0’ = -686 kcal/mol AEROBIC CO 2 is the quantitative measure of the ability of the microrganisms present in the disposal environment to utilize/assimilate the test C-bioplastic, which is the sole C- source available for the microorganisms -- biodegradation/bioassimilation METRIC FOR BIODEGRADABILITY ANAEROBIC Glucose/C-bioplastic 2 lactate;  G 0’ = -47 kcal/mol CO 2 + CH 4

26 Ramani Narayan, Michigan State University O2O2 Compost & Test Materials CO 2 Radiolabelling methodology – longer duration, can use active compost environment (90+% of carbon converted to CO 2 absolute or relative to cellulose/positive control Cellulose curve must plateau and the time period for control and test material must be the same

27 Ramani Narayan, Michigan State University, FUNDAMENTALS -- BASICS BIODEGRADATION -- BIODEGRADABILITY Composting Compostable plastic SoilAnaerobic digestor landfillsmarine ENVIRONMENT IN IN WHAT TIME?

28 Ramani Narayan, Michigan State University BIODEGRADABILITY/BIODEGRADATION  In simple terms, biodegradability measures the capacity of microorganisms present in the disposal environment to completely consume the bio carbon product within reasonable and defined time frame in the specified environment.  Composting is one such environment under which biodegradability occurs (compostable plastic) – In the composting environment:  the description of the environment  the degree of microbial utilization (percent biodegradation)  the time frame within which it occurs are specified through ASTM D6400 (for plastic products), and ASTM D6868 (for coatings on plastic substrates) standards. – In the marine environment the requirements are specified in ASTM D7081

29 Ramani Narayan, Michigan State University HYDRO, OXO, PHOTO PREFIX DOES NOT MATTER!! Test method is material independent HYDROLYTIC OXIDATIVE COMPLETE BIOASSIMILATION/BIODEGRADTION IN DISPOSAL ENVIRONMENT IN SPECIFIED TIME Carbon chain polymers QUESTION IS -- Can the microbial population in the disposal environment completely assimilate/utilize the C-material in one year time frame??? Time & Disposal Environment is the KEY PVOH – YES PE/PS + ADDITIVES – NO, NOT IN THE DISPOSAL ENVIRONMENT AND NOT IN ONE-TWO YEAR TIME FRAME PET –NO PBAT, PBS -- YES CELLULOSE TRIACETATE –NO CA ( around 2.0 ds – yes) PLA (YES, crystallinity is key) Specification Standards D6400, D6868, D7021 EN ISO 17088

30 Ramani Narayan, Michigan State University END OF LIFE OPTIONS COMPOSTING FACILITY COMPOSTING FACILITY RECYCLING FACILITY RECYCLING FACILITY WASTE TO ENERGY FACILITY WASTE TO ENERGY FACILITY Biodegradable Plastics Biodegradable Plastics RECYCLED PRODUCTS LAND APPLICATION recycling polymeric carbon back to soil ENERGY INCINERABLE Anaerobic digestion facility Marine environment Paper-biopolymer composite Landfill X Unless managed for landfill gas recovery for energy BIOBASED PLASTICS

31 Ramani Narayan, Michigan State University Cradle to Cradle Concept for Material Design (Integration of Biodegradable Materials with Disposal Infrasructures) Biodegradable Materials Biodegradable Materials COMPOSTING FACILITY COMPOSTING FACILITY LAND APPLICATION recycling polymeric carbon back to soil TEST METHOD ASTM D5338; ISO & 2 ISO16939 (disintegration) ASTM D6340 C-14 SPECIFICATIONS ASTM D6400; EN ISO ASTM D6868 – paper coatings Waste water treatment facility Waste water treatment facility ASTM D5271 ISO 14851/14852 Anaerobic digestion biogas energy plant ASTM D5511 ISO Soil Mulch film Agriculture appl Soil Mulch film Agriculture appl ASTM D 5988 Marine & fresh water ASTM D 6691,6692 D 7021 specification Ramani Narayan, Michigan State University,

32 Ramani Narayan, Michigan State University DEGRADABLE VS BIODEGRADABLE Biodegradability claim must be qualified by identifying the disposal environment, ensuing complete utilization of the carbon substrate by the microorganisms present in the disposal environment in a short time period – one year or less, and substantiated by the appropriate ASTM, or ISO standards Degradability, partial biodegradability, or will eventually biodegrade is not an option! – serious health and environmental consequences

33 Ramani Narayan, Michigan State University BIODEGRADABILITY Define Time – complete and short (one growing season) Define Disposal Environment like composting Degradability, partial biodegradability, or will eventually biodegrade is not an option! – serious environmental consequences

34 Ramani Narayan, Michigan State University Problems with Degradables – Toxic Chemicals Transport  plastic pieces can attract and hold hydrophobic elements like PCB and DDT up to one million times background levels. As a result, floating plastic is like a poison pill -- toxins are carried up the food chain – birds, fishes, and eventually human – From Algalita Marine Research Foundation –  Plastic residues function as a transport medium for toxic chemicals in the marine environment.  PCBs, DDE, and nonylphenols (NP) were detected in high concentrations in degraded polypropylene (PP) resin pellets collected from four Japanese coasts. – Mato et al Environ. Sci. Technol. 2001, 35,

35 Ramani Narayan, Michigan State University Captain Charles Moore Algalita Marine Research Foundation Plastic fragments with toxins colonized and consumed by birds fishes Transport of toxins up the food chain

36 Ramani Narayan, Michigan State University Major Problems/Issues with Degradable Materials/Products  Thompson, R.C. et al Lost at sea: Where is all the plastic? Science 304, 838, 2004  Plastic debris around the globe can erode (degrade) away and end up as microscopic granular or fiber-like fragments, and that these fragments have been steadily accumulating in the oceans  fragments come from several sources, the researchers suggest. These include mechanical erosion of nondegradable plastic bottles and packaging, nondegradable parts of biodegradable plastics, and plastic pieces used as abrasives in cleaning agents. FLOTSAM Lab experiments show that marine animals consume microscopic bits of plastic, as seen here in the digestive tract of an amphipod. © Science 2004

37 Ramani Narayan, Michigan State University, Biodegradable Plastic Products Space  Confusion  Misunderstanding  Misinformation  Claims without scientific substantiation  GETTING BETTER/MUCH BETTER – ASTM Standards in place  D6400 for composting, D6868 for paper coatings modifiers and additives, D 7021 for marine – specification standards – Certification by BPI based on strict compliance with Standards – Regulations like in CA – Pioneering programs like the one at the city of San Francisco enforcing compliance of Standards – California Waste Management Board study at Chico State showing the applicability of Standards and demonstrating “true completely biodegradable plastics in composting conditions” – Other Community, State, mandates – U.S. Composting Council

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39 Ramani Narayan, Michigan State University ASTM D6954  7.1 The reporting section must clearly and objectively include the proposed real world applications and disposal environments for which the plastic is being developed with indicated exposure and lifetime expectancies.  7.2 Tier 1—The report must identify the following:  Resin grade plus the commercial name of the formulation additive or percent of catalyst concentrations.  NOTE 8—Identification of test samples needs to be sufficient to inform readers of the commercial identification of the formulation and of the additives and their availability in the marketplace.  The proposed disposal medium or media for the plastic must be indicated with anticipated life expectancy noted.  The exposure conditions such as temperature, time, moisture, and oxygen concentrations need to be reported.  The exposure conditions and time of exposure (kJ/m 2·nm at 340 nm) to radiation, if used, must be recorded.  Molecular weight and polydispersity index, tensile elongation, and percentage of gels of the samples before and after the indicated time for abiotic test exposure should be reported.  Complete mass balances are to be reported.

40 Ramani Narayan, Michigan State University ASTM D6954 (Contd)  7.3 Tier 2—The report must state the following:  Extent of biodegradation (carbon dioxide evolution profile to plateau as per standards) and expressed as a percentage of total theoretical carbon balance.  Percentage of gel or other nondegradable fractions.  Volatiles produced by the oxidation process.  Temperature and moisture conditions.  Additions of inoculants and moisture and their timing and any additional mixing procedures.  7.4 Resulting data from Tier 1 combined with data from Tier 2 for comparison and ranking of polymers under test.  7.5 Tier 3—The report shall include the following:  Detailed description of preparation of material for testing.  Specific testing performed as described in 6.9 with particular emphasis on any deleterious effects of the soil or aquatic additive.  Regulated metal concentrations, pH, and ability to hold and percolate water before and following oxobiodegradation testing.  NOTE 5—For determining biodegradation rates under composting conditions, Specification D 6400 is to be used, including test methods and conditions as specified.

41 Ramani Narayan, Michigan State University ASTM D 6954 contd -- NOTE  NOTE 5—For determining biodegradation rates under composting conditions, Specification D 6400 is to be used, including test methods and conditions as specified.  At least one temperature must be reasonably close to the end use or disposal temperature, but under no circumstances should this be more than 20°C away from the removed that temperature. It must also be established that the polymer does not undergo a phase change, such as glass transition temperature (Tg) within the temperature range of testing  Standard Guide for Exposing and Testing Plastics that Degrade in the Environment by a Combination of Oxidation and Biodegradation

42 Ramani Narayan, Michigan State University  ASTM D6400 identified 3 criteria Mineralization (D5338):  Conversion to carbon dioxide, water & biomass via microbial assimilation  60% of carbon conversion to CO2 for homopolymer & 90% carbon conversion to CO2 for block, segmented copolymers, and blends, including addition of low MW additives  Same rate as natural materials Leaves, paper, grass & food scraps  Time days or less; if radiolabeled polymer is used 365 days or less Disintegration  <10% of test material on 2mm sieve – Safety  No impacts on plants, using OECD Guide 208  Regulated (heavy) metals less than 50% of EPA (USA, Canada) prescribed threshold Specification Standard for Biodegradable/Compostable Plastics Basis for standards in Europe, Japan, China, Korea, Taiwan O2O2 Compost & Test Materials CO 2

43 Ramani Narayan, Michigan State University TERMINOLOGY BIOBASED (RENEWABLE) Organic material containing in whole or part biogenic (biological sources) carbon Refers to using biomass or crop feedstock (New carbon) vs petroleum or fossil feedstock (OLD carbon) Reducing carbon footprint BIODEGRADABILITY END-OF-LIFE option – integrated with disposal systems like composting, and anaerobic digestion or marine or soil functional property attribute to be designed and engineered into a biobased product when needed or necessary!! BIOMATERIALS Refers to: Any material (metal, plastic, ceramic) implanted in the body -- design and engineering considerations different; biodegradability considerations different Biomedical applications


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