OECD Global Forum on Environment - Plastics in a Circular Economy, 29-31 May 2018

1. Challenges’ towards sustainable plastics design from
feedstock to end of life
Ramani Narayan
University Distinguished Professor
narayan@msu.edu
If you use any of the slides/materials, please reference authorship and affiliation (Ramani Narayan, Michigan State
University) – thank you -- Copyright Ramani Narayan
OECD Global Conference on Environment
Plastics in a Circular Economy - Design of Sustainable Plastics from a Chemicals
Perspective
May 29-31 , 2018 Copenhagen, Denmark

2. Narayan
OECD –working scheme
on life cycle of plastics
“from plant biomass like agricultural crops and
residues, marine and forestry materials, algae, and
fungi living in a natural environment in equilibrium
with the atmosphere” – BIOBASED PLASTICS
ISO 1660 series standards –Plastics Biobased content Parts 1 through 5
ISO DIS 22526 Carbon and environmental value proposition – general principles
(Pt 1); material carbon footprint (Pt 2) Process carbon footprint (Pt 3)

3. BASICS -- TERMINOLOGY
Biobased plastics and products refers to:
 Origins of the carbon in the polymer
 Plant-biomass feedstock (biobased/renewable) vs petro-fossil feedstock
 The “beginning of life” and does not address end-of-life
 Biobased products are not necessarily and automatically biodegradable-compostable
H2C CH2
n
PE
C
O
O CH2 CH2 OC
O
n
PET
CH
CH3
C
O
O
PLA
n
Biobased polyester
Biobased polyurethane
Cellulose

4. Narayan
Carbon footprint reduction strategy using bio content
4
CO2 + H2O (CH2O)X + O2
photosynthesis
sunlight energy
Plant-Biomass, Ag & Forestry
crops & residues
NEW CARBON
Petro-Fossil Resources (Oil, Coal, Natural gas) -- OLD
CARBON
> 106 YEARS
1-10 years
PRODUCTS
biobased –containing organic carbon of renewable origin from agricultural, plant, animal, fungi,
microorganisms, marine or forestry materials living in a natural environment in equilibrium with the
atmosphere.
12C (98.89%); 13C (1.1%); 14C (1x10-10 )
14C/12C = ~ 10-12 in the atmosphere in equilibrium with
plant-biomass living systems
14C t0.5 = 5730 years; so fossil carbons
have no 14C carbons remaining -- zero
radioactivity
Biobased carbons will have the same
14C radioactivity as in plant biomass
and in the atmosphere – providing a
tracer for carbon in the environment
to product molecule
ASTM D6868; ISO 16620 (Pt 2) -- Fundamentals
The amount of 14C is measured relative to a more abundant isotope (i.e., 13C or 12C) in the ion beam of an AMS (accelerator
mass spectrometry) or by decay counting. Absolute quantification comes from comparing the sample's measured isotope ratio
to that of pre 1950 biobased oxalic acid radiocarbon Standard Reference Material (NIST SRM) 4990c, (referred to as HOxII) after
correcting for isotopic fractionation. Values must also be corrected for the C-14 pulse injected into the atmosphere (1950-63) from
atmospheric testing of nuclear weapons

5. Narayan
Years % decay
0 0
25 0.3
50 0.6
75 0.9
100 1.2
50
10
1
0
10
20
30
40
50
60
70
80
90
100
0 10000 20000 30000 40000
%RadioactivityRemaining
Years
Radioactive decay of C14
(-dN/dt=λ*N)
N = No*exp(-λ*t)
λ = ln 2/(t1/2) ; t1/2 = 5730 years
Products containing biobased carbons -- carbon
originating from “ living systems (plant biomass) in a
natural environment in equilibrium with the
atmosphere” will retain the same isotopic ratio for 100
years.
Comparing the isotopic ratio of the test product with a
100% biobased standard product provides the amount
of biobased carbons in the test product. Fossil carbons
will have zero radioactivity left as they are formed over
millions of years.

6. Narayan
Exemplar: PLA

7. Narayan
For bottles:
37.5 MM tons PET used
17.2 MM tons CO2 removal from
the environment – equivalent to
40 million barrels of oil/yr
savings
Exemplar -- biobased polyethylene terephthalate --
PET
1.42 kg of CO2 removed from the environment for every kg
of bio-MEG produced

8. Narayan
OECD –working scheme
on life cycle of plastics
Biobased plastics X X
Land, oceans,
biodegradable-compostable plastic representing the “end-of-life”.
“Certified Compostable BioPlastic”
ISO series standards – ISO TC61/SC14
ISO 18600 SERIES STANDARDS – ISO TC122 ON PACKAGING
ISO 18606 -- Packaging and the environment — Organic recycling
Emballage et environnement — Récyclage organique

9. Narayan
Question:
Is biodegradability a solution to plastics end-of-life?
Biodegradability in concert with (integrated to) managed, closed-loop disposal
systems like composting/anaerobic digestion or soil (agriculture) can be a viable
and responsible “end-of-life” solution in harmony with the “Circularity Model”

10. Narayan
CAUTION:
Unqualified use of the term “biodegradable” is wrong, misleading, and deceptive.
It violates the law in the State of California and U.S. Federal Trade Commission (FTC)
green guides & in Australia too
 Need to define disposal environment, time/rate and extent of biodegradation
– qualified biodegradability claim
 Integrated to Composting or AD coupled to composting or soil
biodegradability (mulch films & ag products)
• Need complete microbial assimilation and removal from the environmental
compartment in a short time period otherwise may have environmental and health
consequences
• Degradable, partial biodegradable not acceptable – serious health and
environmental consequences
• Phil. Trans. Royal. Soc. (Biology) July 27, 2009; 364

11. Narayan
Certified/ Verified Compostable Plastics is the “enabling technology” to efficiently and
efficaciously divert food and other organic wastes from landfills to environmentally
responsible end-of-life solutions like composting and anaerobic digestion.
 Green Sports Alliance – sports team events
 Schools & College (U of Michigan, Penn State, Michigan State)
 Corporate campuses (Google)
 Venues and events, airport concourses
 Cities – San Francisco, Seattle and others
Enabler for the “Circularity Model”
Enabler for “Organics Recycling”
“Compostable” defines the boundary conditions under which complete
biodegradation (microbial utilization) needs to be validated using ASTM/ISO
International Standards

12. Generated Recovered percent Discarded
EPA, MSW numbers 2013
Wt. recovered mtons GHG benefits (MMT CO2-eq)
EPA warm model , 2013

13. Narayan
1. Marine environment – IS NOT A DISPOSAL ENVIRONMENT and
therefore designing for biodegradability in a marine environment IS
NOT A SOLUTION
2. There may be value(?) to have the property of “biodegrability”
engineered into products used in marine environments – in case they
are “inadvertently” lost. However, even these biodegradable plastics
can persist over a long period of time in many ocean environments and
could have negative environmental impacts – SO
BIODEGRADABILITY IS NOT A SOLUTION
What about the Marine/ocean environment?
What about biodegradability in LANDFILLS & LITTER
--Uncontrolled disposal environments and no closing of the loop is possible –
not compatible with the “Circularity Model”

14. Carbon footprint reduction strategy using bio contentBasics of microbial utilization -- biodegradability
14
 Microorganisms utilize carbon substrates as “food” to extract chemical
energy for their life processes.
 They do so by transporting to the C-substrate inside their cells and:
 Under aerobic conditions, the carbon is biologically oxidized to CO2
releasing energy that is harnessed by the microorganisms for its life
processes. Under anaerobic conditions, CO2+CH4 are produced.
 Thus, a measure of the rate and amount of CO2 or CO2+CH4 evolved as
a function of total carbon input to the process is a direct measure of the
amount of carbon substrate being utilized by the microorganism
(percent biodegradation)
Glucose/C-bioplastic + 6 O2
6 CO2 + 6 H2O; DG0’ = -686 kcal/mol
Glucose/C-bioplastic 2 lactate; DG0’ = -47 kcal/mol
CO2 + CH4

15. Ramani Narayan, Michigan State University
More Biodegradation Facts
The aerobic oxidation process (a highly specialized cellular phenomenon)
requires the participation of three metabolically interrelated processes:
1. Tricarboxylic acid cycle (TCA cycle)
2. Electron transport
3. Oxidative phosphorylation
All of the processes take place inside the cell

16. 0
10
20
30
40
50
60
70
80
90
100
0 20 40 60 80 100 120 140 160 180 200
Time (days)
%CconversiontoCO2(%biodegradation)
lag
phase
biodegradation phase
plateau phase
biodegradation degree
O2
Compost
& Test
Materials
CO2
ASTM D5338; ISO 14855; ISO 18606; EN 13432
AS 4736 & 5810
level of biodegradation needed to claim
safe and efficacious removal of the plastic
carbon from the environmental
compartment
Figure 3. Measuring rate and extent of biodegradability using test plastic
as the sole carbon source

20. Post consumer Food Waste Composting
General Motors – Milford Proving Ground Case Study
Melissa Phipps
May 18, 2017
 Est. 1924
 3,899 acres
 > 100 buildings
 5,000 employees
 135 lane miles
 One cafeteria serving approx. 650 people / day

21. Recover organics from the landfilled waste stream for composting at a
local facility without dramatically increasing operational costs.
GM-MPG is one of nine GM – North American facilities which
participates in compostable waste collection. The size and scope of the
MPG program, however, made implementation an unusual challenge.
THE CHALLENGE
Certified compostable food
service ware & bin liners

22. 2 2
SEGREGATION IN ACTION About 12,000 lbs recovered for composting

23. Narayan
Marine microbes digest plastic
28 March 2011 | Nature | doi:10.1038/news.201.191
Mealworms will dine on polystyrene foam when they can’t get a better meal(Environ.
Sci. Technol. 2015, DOI: 10.1021/acs.est.5b02661).
Polyethylene bio-degradation by caterpillars of the wax moth Galleria mellonella
Current Biology 27, R1–R3, April 3, 2017
A bacterium that degrades and assimilates poly(ethyleneterephthalate)
Science, 2016
Mutant enzyme biodegrades PET 20% faster (PNAS, 2018)
Plastics biodegradability stories --

24. Narayan
TAKE HOME MESSAGE
 Recent articles in literature and widely covered in print and E-media of macro-organisms like meal
worms and wax moth eating plastics as solutions for plastic waste management are misleading,
troublesome and irresponsible.
 It takes away from serious end-of-life solutions in place and being developed
 Biodegradability is not a magical solution for plastics waste management.
 Complete biodegradation of single use disposable plastics along with food and other biowastes in
managed, closed loop disposal systems like composting and anaerobic digestion is environmentally
responsible. This helps divert food and other biowastes from landfills and oceans.
 Certified Compostable BioPlastics
 Degradation resulting in release of small fragments (microplastics) into the terrestrial and ocean
environment has been shown to cause harm to the environment and to human health.
 Many papers in the literature document that such fragments pick up toxins from the environment
like a sponge and become a vehicle to transport toxins up the food chain.
 Use biobased, renewable carbon feedstocks (carbon footprint reductions) and in harmony with the new
“Circular Economy” model