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Bioplastics and Petroleum-based Plastics:Strengths and WeaknessesF. Gironi a & V. Piemonte aa Department of Chemical Engineering, Materials & Environment,University of Rome, Rome, Italy

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Energy Sources, Part A, 33:1949–1959, 2011

Copyright © Taylor & Francis Group, LLC

ISSN: 1556-7036 print/1556-7230 online

DOI: 10.1080/15567030903436830

Bioplastics and Petroleum-based Plastics:

Strengths and Weaknesses

F. GIRONI1

and V. PIEMONTE1

1Department of Chemical Engineering, Materials & Environment,

University of Rome, Rome, Italy

Abstract The application of biomass, such as starch, cellulose, wood, and sugar,

used to substitute fossil resources for the production of plastics, is a widely acceptedstrategy towards sustainable development. In fact, this way a significant reduction

of non renewable energy consumption and carbon dioxide emission is accomplished.In recent years, several typologies of bioplastics were introduced and the most im-

portant are those based on cellulosic esters, starch derivatives, polyhydroxybutyrate,polylactic acid, and polycaprolactone. Nowadays, the most important tool to evaluate

the environmental impact of a (bio)plastic is the life cycle assessment that determinesthe overall impact of a plastic on the environment by defining and analyzing several

impact categories index like the global warming; the human toxicity; the abioticdepletion; the eutrophication; the acidification; and many others directly related to

the production, utilization, and disposal of the considered plastics. The aim of thiswork is to present a comparison between bioplastics and conventional plastics through

the use of the “Life Cycle Assessment” methodology. In particular, the life cycle

assessment’s Cradle to Grave of shoppers made from Mater-Bi (starch-based plastic)an polyethylene were reported and compared as a case study in order to highlight

the strengths and weaknesses of the bioplastics and the conventional plastics.

Keywords bioplastics, environmental impact, mater-bi, life cycle assessment, re-newable resources

1. Introduction

Nowadays the worldwide production of bioplastics is about 750,000 tons/year and is

very modest when compared with 200 million tons/year of conventional plastics derived

from petroleum; it is estimated that in the near future, the growth will be exponential,

reaching about 1,000,000 tons/year in 2011 (Widdecke et al., 2008). The major manu-

facturers are Nature Works (with a production of 140,000 tons/year of polylactic acid

[PLA]) and Novamont (with a production of 35,000 tons/year of Mater-bi, starch-based

bioplastics).

The interest in the development of biodegradable plastics noticed in recent years is

due to motives of both environmental and strategic nature (Zhang et al., 2000; Demirbas,

2007; Anderson et al., 1998; Gross and Kalra, 2002). As a matter of fact, in order to

reduce the environmental impact of plastics (especially in terms of CO2 released in the

environment) some of the products obtained from agriculture (starch, cellulose, wood,

Address correspondence to Dr. Vincenzo Piemonte, Department of Chemical Engineering,Materials & Environment, University of Rome, via Eudossiana 18, Rome 00184, Italy. E-mail:piemonte@ingchim.ing.uniroma1.it

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sugar) are used as raw materials. This way the net balance of carbon dioxide is greatly

reduced, since the CO2 released during production, utilization, and disposal of plastics

is balanced by the CO2 consumed during the growth cycle of the plant. Furthermore,

petroleum, with a constantly rising price, is replaced by renewable raw materials obtained

from agriculture.

Several biopolymers are produced from fermentative processes of natural valuable

raw materials, such as wheat, corn, sugar, rice, potatoes, and soya. Specific consumption

per unit of biodegradable plastic produced is different (Harding et al., 2007) depending

on the raw material used, but there is no doubt that these raw materials will be taken away

from other uses, in particular from alimentation, with a consequent increase in the cost

of food. From this point of view, it is clear that the development of bioplastics requires

the use of less valuable raw materials, such as agricultural or food industry wastes or

from the use of non edible genetically modified plants, which may be grown in lands

(e.g., mountains) not suitable for the production of food.

The use of bioplastics was also stimulated by a second environmental motive, related

to problems connected with the disposal of waste: in the 1990s, the main system for the

disposal of municipal solid waste (with a fraction of plastics equaling 20–30%) was the

disposal in landfill. Traditional plastics undergo degradation phenomena with very slow

kinetics; hence, the volume required by these materials in landfills is virtually stable over

time. On the contrary, bioplastics show higher degradation rates in landfills (Ishigaki

et al., 2004) and, therefore, the required volumes can be contained.

Currently the market suggests several typologies of bioplastics, among which the

most important are those based on cellulosic esters (Hoppenheidt and Trankler, 1995),

starch derivatives (TPS) (Bastioli, 2005), polyhydroxybutyrate (PHB) (Harding et al.,

2007), polylactic acids (PLA) (Tokiwa and Calabia, 2006), and polycaprolactone (PCL)

(Demirbas, 2007). Application fields range from uses in the pharmaceutical and biomed-

ical area as potential biocompatible materials for artificial protheses, for sutures, and

as a medium for controlled drug release; in the field of packaging, including food and

shoppers; and in the field of agriculture as mulching films (Widdecke et al., 2008).

Nowadays, the development of bioplastics is hampered by higher costs of production

of these materials as opposed to traditional plastics; however, a thorough analysis con-

sidering not only the cost of production but also the costs associated with the managing

of waste might lead to various results.

In this article, the main features of bioplastics will be discussed, highlighting the

problems linked with their biodegradation and with possible scenarios for their disposal.

Therefore, in order to provide first considerations on the strengths and weaknesses of

the conventional plastics and bioplastics, the results reported in different literature life

cycle assessments (LCAs) studies (Harding et al., 2007; Hoppenheidt and Trankler,

1995; Bastioli, 2005; Patel, 2002; Krueger et al., 2009) were analyzed and discussed.

Furthermore, an original “cradle to grave” LCA study (from the raw materials up to the

final disposition of the analyzed product) focused on the comparison between shoppers

made from Mater-Bi and polyethylene (PE) is reported as a Case Study.

2. The Biodegradability Matter

In accordance with ASTM D 6400, biodegradable plastics are only those whose degra-

dation occurs as a result of natural action of microorganisms, such as bacteria, fungi, and

algae, in a limited period of time and in absence of ecotoxic effects.

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Aerobic or anaerobic biodegradation may occur and the process that completely

degradates the polymer into biomass is called “Complete Biodegradation,” while if the

original polymer is completely converted in gas and minerals we have a “Mineralization.”

In any case, the biodegradation takes place in two phases: an initial phase in which

microorganisms launch a chemical attack on the polymer chain aimed at the breaking

of chemical bonds, and a second phase of real biodegradation. These two phases are

strongly controlled by the presence of numerous factors, both endogenous (as molecular

weight, crystallinity, flexibility of the molecule) and exogenous (temperature, humidity,

pH, availability of oxygen, enzymatic activity) that can, therefore, alter and/or modify

the outcome of the biodegradation process itself (Kale et al., 2007b).

As reported by Davis and Song (2006), the most favorable final disposition, from

an environmental point of view, for a bioplastics is represented by the composting

process that transforms, by a biodegradation process, the disposed product into a soil-

like substance called humus, CO2, water, and inorganic compounds and leaves no visible,

distinguishable, or toxic residues. Indeed, with regard to recycling, nowadays processes

for selecting and recycling bioplastics are not yet developed, despite what happens

for conventional plastics. The composting of bioplastics can, therefore, be an optimal

solution, taking into account that the process conditions in terms of temperature, humidity,

oxygen, etc. must be strictly controlled if we want to achieve appreciable results in terms

of final products. The work of Kale et al. (2007a) concerning the biodegradation of PLA

bottles under controlled and natural conditions is interesting. The experimental results

show that the efficiency of degradation in a natural environment is equal to approximately

10–20% of efficiency in a controlled environment.

Additives are often present in the bioplastics, mainly to improve the mechanical

properties of the obtained material. This choice may not only cause a reduction in the

biodegradability of plastics and other serious ecotoxic effects, but it might even determine

the non-compostability of the bioplastic, making in fact, a vain every advantage achievable

through the use of a bioplastic.

3. Bioplastics and Petroleum-based Plastics:How to Compare?

If on the one hand, the real biodegradation of a plastic represents an extremely delicate

problem, certainly a key aspect in assessing the applicability or not of bioplastics is the

impact on the environment resulting from their use, during the entire life cycle from

production to final disposal (cradle to grave). This type of analysis is called Life Cycle

Analysis (LCA) and is based on finding some factors considered crucial in assessing the

impact that a particular product can have on the environment. Among the most important

factors or indices of environmental impact there are:

Abiotic depletion: the characterization factor is the potential of abiotic depletion of the

extraction of those minerals and fossil fuels. The unit of the characterization factor

is kg of antimony (Sb) equivalents per kg of extracted mineral.

Global warming: the characterization factor is the potential of global warming of each

greenhouse gas emission to the air. The unit of the characterization factor is kg of

carbon dioxide (CO2) equivalents per kg of emission.

Human toxicity: the characterization factor is the potential of human toxicity of toxic

substances emitted to the air, water, or/and soil. The unit of the characterization

factor is kg of 1,4-dichlorobenzene (1,4-DB) equivalents per kg of emission.

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Fresh water aquatic ecotoxicity: the characterization factor is the potential of fresh water

aquatic toxicity of each substance emitted to the air, water, or/and soil. The unit of

this factor is kg of 1,4-DB equivalents per kg of emission.

Marine aquatic ecotoxicology: the characterization factor is the potential of marine

aquatic toxicity of each substance emitted to the air, water, or/and soil. The unit

of this factor is kg of 1,4-DB equivalents per kg of emission.

Terrestrial ecotoxicity: the characterization factor is the potential of terrestrial toxicity of

each substance emitted to the air, water, or/and soil. The unit of this factor is kg of

1,4-DB equivalents per kg of emission.

Photochemical oxidation: the characterization factor is the potential of photochemical

ozone formation of each substance emitted to the air. The unit of this factor is kg of

ethylene (C2H4) equivalents per kg of emission.

Acidification: the characterization factor is the acidification potential for each acidifying

emission to the air. The unit of this factor is kg of sulfur dioxide (SO2) equivalents

per kg of emission.

Eutrophication: the characterization factor is the potential of eutrophication of each

eutrophying emission to the air, water, and soil. The unit of this factor is kg of

phosphate ion (PO4-) equivalents per kg of emission.

Tables 1 and 2 show a collection of LCA literature data (Patel, 2002, 2005); each

LCA characterizes and compares the environmental impact of various bioplastics (ther-

moplastic starch (TPS), polylactic acid (PLA), and polyhydroxyalkanoates (PHA) and

traditional plastics (high and low density polyethylene, Nylon 6, polyethylene terephta-

late (PET), polystyrene (PS), polyvinyl alcohol (PVOH) and polycaprolactone) with an

approach cradle to grave. The comparison is given on the basis of some of the most

important indices of environmental impact cited above.

Table 1

Energy required from non-renewable sources and CO2 emissions for different types of

plastics currently on the market

Type of plastic

Energy

requirement, MJ/kg

Global

warming, kg CO2 eq/kg

From non-renewable sources

HDPE 80.0 4.84

LDPE 80.6 5.04

Nylon 6 120.0 7.64

PET 77.0 4.93

PS 87.0 5.98

PVOH 102.0 2.70

PCL 83.0 3.10

From renewable sources

TPS 25.4 1.14

TPS C 15% PVOH 24.9 1.73

TPS C 60% PCL 52.3 3.60

PLA 57.0 3.84

PHA 57.0 Not Available

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Table 2

Eutrophication and acidification for different types of

plastics currently on the market

Type of plastic Acidificationa Eutrophicationb

Pellets

LDPE (1 kg) 17.4 1.1

TPS (1 kg) 10.9 4.7

Starch foam (1 kg) 20.8 2.8

Starch film (1 kg) 10.4 1.1

Loose fills

Starch foam (1 m3D 10 kg) 276.0 39.0

PS foam (1 m3D 4 kg) 85.0 8.0

Films and bags

TPS (100 m2) 239.0 103.0

Starch-polyester (100 m2) 26.5 2.8

PE (100 m2) 236.0 15.0

a(g SO2 eq).b(g PO3

4eq).

Overall, the data reported in Tables 1 and 2 show how the production and use

of bioplastics is more advantageous compared to conventional plastics from the energy

demand and emissions of greenhouse gases point of view. On the contrary, they have

a strong impact on the environment for acidification of soil and the eutrophication,

mainly because of the use of fertilizers and chemicals in the cultivation of renewable

raw materials used for the production of bioplastics. However, it should be pointed out

that the presence of non-biodegradable copolymers in bioplastics (see Table 1) decrees a

significant increase in energy demand and CO2 emissions compared to bioplastics. Indeed,

in an attempt to improve the performance of mechanical biopolymers, non-biodegradable

copolymers are added thus reducing the biodegradable power of the obtained material. It is

important to stress that the results of above LCA were obtained using the incineration with

energy recovery as final provision: this choice is not particularly favorable to bioplastics

mainly for their low calorific value.

The analysis of LCA data, always show that bioplastics have some indices of

environmental impact lesser than those of other traditional plastics, while other indices

are in favor of the latter; hence, the need to determine an index of overall environmental

impact where all indices can be incorporated and adequately weighed.

To that end, there are various methods for weighting factors of environmental impact,

aimed precisely to the determination of a single global index. One of the methods most

often used in the LCA is called “distance-to-target” (Weiss et al., 2007), which deals

directly a pair of plastics to compare (for example PLA and PE) providing a single index

of environmental impact on the pair itself.

In this regard, Figure 1 shows the value of the cumulative index of environmental

impact for a couple of products of commercial interest. Zero values of this index indicate

a substantial “balance” between the two materials in terms of environmental impact.

Positive values indicate a conventional plastic superiority, while negative values

indicate a lower environmental impact of bioplastics. The data seem to be entirely in

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Figure 1. Values of the overall environmental impact for several plastic-bioplastics pairs evaluated

with the “distance to target methodology.” (color figure available online)

favor of bioplastics, with the exception of two cases (regarding packaging with PLA and

loose-fills-based starch compared with polystyrene). However, since that methodology

defines the weight of the various indices of environmental impact depending on the

target of each index, it is clear that the results are strongly influenced by the criteria of

choice and priorities that are given to each category of environmental impact.

Another possibility to give an overall impact index is to group the impact categories

into three macro-categories: Human Health, Ecosystem Quality, and Resources as pro-

posed by the Ecoindicator-99 methodology (Goedkoop et al., 2000). Then we must assign

a weight to the individual macro-category and define a global index of the impact I given

by:

I D

X

i

pi ci ;

where pi is the assigned weight to the macro-category of impact i and ci is the value of

the macro-category of impact. The result in terms of convenience of a conventional or a

new generation product is a function of the importance that will be assigned to individual

macro-categories.

Representing the three categories in a “mixing diagram” (Figure 2), each point within

the triangle represents a weighting combination. In each point of the mixing triangle, the

relative weights always add up to 100%. Therefore, the weighting question is, how much

weight out of 100% is attached to each of the three safeguard subjects. In a mixing

triangle, each corner represents a weight of 100% for one safeguard subject; in Figure 2,

the top corner is the weighting combination where “Ecosystem Quality” is weighted

100%, and 0% weight is given to both “Human Health” and “Resources.” Opposite

each corner is the 0%-weight line for this safeguard subject: Any point on the base of

the triangle of Figure 2 gives 0% weight to “Ecosystem Quality,” and the weights are

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Figure 2. Weighting problem: triangle diagram solution. (color figure available online)

split between “100% Human Health/0% Resources” in the bottom-left corner to “0%

Human Health/100% Resources” in the bottom-right corner. We only consider positive

weights, that is, a positive impact score always means a damage: only points within

the mixing triangle are taken as reasonable weighting sets. The figure shows two sets of

weights corresponding to point A (60% Ecosystem Quality, 20% Human Health, and 20%

Resources) and B (40% Ecosystem Quality, 30% Human Health, and 30% Resources). In

the A condition it is more convenient to use Product 1 while in the B one it is preferable

to use Product 2: the focus on one or other product is a function of the weight that will

be assigned to individual macro-categories of impact. The border area between the two

regions is the so-called “line of indifference” that is the set of values of the weights

assigned to bring the two products tested to have the same overall impact index, and thus

a condition of substantial equilibrium between the two products analyzed.

4. Case Study: Mater-Bi vs. PE Shoppers

In the following, we compare the results obtained from our LCAs on shoppers made

from Mater-bi and PE using the Ecoindicator-99 methodology (Goedkoop et al., 2000).

This LCA methodology considers 11 impact categories: Carcinogens, Respiratory Or-

ganics, Respiratory Inorganics, Climate Change, Radiation, Ozone Layer, Ecotoxicity,

Acidification/Eutrophication, Land Use, Minerals, and Fossil Fuels. The first six impact

categories are then be normalized and grouped in the macro-category “Human Health”

that considers the overall impact of the emissions associated to the product analyzed

on the human health; the categories Ecotoxicity, Acidification/Eutrophication, and Land

Use flow in the macro-category “Ecosystem Quality” considers the overall damage on the

Environment, while the “Minerals” and “Fossil Fuels” are grouped in the macro-category

“Resources” that accounts for the depletion of non renewable resources.

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The LCAs were performed by using the SimaPro7 software, while the data of LCIs

were taken both from the Ecoinvent v.2 and the Buwal 250 libraries. The data about the

Mater-Bi production (provided directly from Novamont, with data relating to production

in Terni, Italy) are updated to 2004 (Ecoinvent v2) and refers to a co-polymer with a

starch content of 35% and the left 65% are biodegradable polyester derived from non

renewable sources (polyester type not specified). For the PE, the production process of

granules was performed on average data, for various production sites throughout Europe,

contained in the Eco-profiles prepared by the European Plastics Industry (Buwal 250,

data updated to 2002).

The main assumptions made to perform the LCAs are:

Nature is not part of the production system, this implies that all the emissions

(fertilizers, pesticides, etc.) relative to the area allocated for agricultural production are

strictly taken into account.

As for the biodegradable polyester contained in the co-polymer Mater-Bi, it has been

considered the PCL (biodegradable polyester made from fossil fuels) (Demirbas, 2007).

The production of Mater-Bi and PE shoppers is achieved through three phases:

Production of granules, transportation of granules in the processing establishments, and

process of production of the shoppers by blow foil extrusion.

The LCAs have been realized on the basis of 1,000 shoppers made from Mater-Bi

(total weight of 68 kg) and PE (total weight of 52 kg), respectively. The different weight

between the two shoppers is due to different mechanical properties of the Mater-Bi and

PE, that is to obtain shoppers with the same mechanical characteristics, different thickness

of polymer films are needed (Davis, 2003).

The composting process has been chosen as the best disposal scenario for the

shoppers made from Mater-Bi. In particular, it was considered a degradation of Mater-Bi

by 60% (the remaining 40% is divided between biomass and recalcitrant residue) in the

presence of oxygen, such that 95% of the degraded carbon evolves in CO2. The remaining

5%, assuming the presence of small anaerobic pockets (due to not perfect mixing of the

medium) is considered to evolve in CH4 (Hofstetter et al., 2008). Furthermore, the model

provides the treatment of the collected water in appropriate facilities and municipal waste

disposal by incineration for not composted wastes, including relative emissions.

The Recycling was chosen as the best disposal scenario for the shoppers made from

PE. The production efficiency of PE granules from recycled waste is about 90% (1 kg

recycled shoppers produce 0.9 kg of granules). Transportation and energy are considered

requirements of the selection and reprocessing processes. Furthermore, we assume that

the material obtained downstream of the process is being used for production in place of

virgin material.

The results of the LCAs “cradle to gate” are reported in Figures 3 and 4 in terms of

macro-categories of damage and mixing diagram for the weighting.

Figure 3 shows how the production of Mater-Bi shoppers has a strong impact in

terms of damage to quality of the ecosystem (it is worth noting that this macro-category

includes the impact categories “acidification,” “eutrophication,” “ecotoxicity,” and “land

occupation”). On the contrary, the effects on human health are roughly the same for

both Mater-Bi and for PE. Finally, from Figure 3 it is evident that the greater damage,

in terms of consumption of non-renewable resources (like petroleum-based resouces), is

determined by the shoppers made from PE with respect to that made from Mater-Bi.

The diagram of Figure 4 shows how the two products, using the set of weights

suggested by the LCA Suisse group (40% Human Health, 40% Ecosystem Quality, and

20% Resources) (Krueger et al., 2009), are roughly equivalent in terms of environmental

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Figure 3. Comparison LCA “cradle to gate” on the production of Mater-Bi and PE shoppers.

(color figure available online)

impact. On the one hand, the bioplastics allow saving in terms of fossil resources, on the

other hand, they cause more damage in terms of the ecosystem since the use of different

chemicals (pesticides, herbicides, fertilizers) is particularly harmful both for humans and

the environment.

As for the disposal scenarios of the two products, a very interesting result was

obtained considering the comparison of the LCAs cradle to grave reported in Figure 5. As

you can see from the figure, the Mater-Bi shoppers show a higher impact respect to the PE

shoppers for all three damage categories; hence, all the possible weighting sets provide

the same result: the recycling of the PE shoppers have a lower overall environmental

impact than the Mater-Bi shoppers. The advantages, in terms of environmental impact,

derived from the saving of the non renewable resources that can be achieved by the

Figure 4. Weighting problem: comparison between Mater-Bi and PE shoppers. (color figure avail-

able online)

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Figure 5. Comparison LCA “cradle to grave” for the composting of Mater-Bi shoppers and the

recycling of PE shoppers. (color figure available online)

recycling of a conventional plastic are much higher than the advantages derived from

the production of compost. On the other hand, materials that can only have a certain

destination, such as the plastic used for bags for the collection of organic wastes, remain

outside of this type of consideration. In this case, the final destination can only be the

composting together with organic waste itself.

5. Conclusions

The literature studies show, in general, a superiority of bioplastics in terms of consumption

of non-renewable sources and emissions of greenhouse gases, whereas it would be prefer-

able for conventional plastics with regard to the impact indices related to acidification and

eutrophication. Obviously, depending on the weight given to the various indices of envi-

ronmental impact, we may give preference either to bioplastics or conventional plastics.

The LCA studies conducted to compare the environmental impact of the Mater-Bi

with that of a conventional plastic, such as PE, in terms of impact associated with the

production of the shoppers, yield a result only apparently controversial: the comparison

appears almost at par. This result must be interpreted considering that, if on one hand, the

bioplastic can save in terms of fossil resources, the other causes major damage in terms

of ecosystem quality because for the production of raw material (corn) it is necessary to

use an intensive agriculture with the use of different chemicals (pesticides, herbicides,

fertilizers) that are harmful to the environment. The superiority of the Mater-Bi on the

PE does not seem so obvious, but on the contrary, giving a high weight to both “human

health” and “ecosystem quality” the Mater-Bi “failed” in comparison. This result can

be generalized to other pairs of bioplastics/conventional plastics with close areas of

employment, such as PET and PLA. Therefore, the true advantage of the bioplastics is

represented by the use of renewable resources, but the benefit is paid in environmental

terms due to the impact on ecosystem quality caused by the use of pesticides and fertilizers

and by the consumption of land and water.

As for the disposal scenarios, the comparison of the LCAs cradle to grave for the

two products analyzed has pointed out the superiority, in terms of overall environmental

impact, of the recycling of conventional plastics on the composting of bioplastics. On

the other hand, the LCAs performed do not consider the advantages derived from the use

of biodegradable products, such as bags for the collection of organic wastes or cuterly

disposable, that can be disposed directly with the organic wastes avoiding the energetic

and logistical costs of the processes of collection and sorting of the wastes.

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Acknowledgments

The authors wish to thank CONAI for their useful contributions.

References

Anderson, J. M., Hiltner, A., Wiggins, M. J., Schuber, M. A., Collier, T. O., Kao, W. J., and Mathur,

A. B. 1998. Recent advances in biomedical polyurethane biostability and biodegradation.

Polymer Intl. 46:163–171.

Bastioli, C. 2005. Starch-Based Technology. In: Handbook of Biodegradable Polymers. Shrewsbury,

MA: Rapra Technology Limited, pp. 257–286.

Davis, G. 2003. Characterization and characteristics of degradable polymer sacks. Mater. Character.

51:147–157.

Davis, G., and Song, J. H. 2006. Biodegradable packaging based on raw materials from crops and

their impact on waste management. Indus. Crops & Products 23:147–161.

Demirbas, A. 2007. Biodegradable plastics from renewable resources. Energy Sources Part A

29:419–424.

Goedkoop, M., Effting, F., and Collignon, M. 2000. The Eco-indicator 99, A Damage Oriented

Method for Life Cycle Impact Assessment, second edition. Amersfoort, the Netherlands: PRé

Consultants B.V.

Gross, R. A., and Kalra, B. 2002. Biodegradable polymers for the environment. Gren Chem.

297:803–807.

Harding, K. G., Dennis, J. S., von Blottnitz, H., and Harrison, S. T. L. 2007. Environmental analysis

of plastic production processes: Comparing petroleum-based polypropylene and polyethylene

with biologically-based poly-ˇ-hydroxybutyric acid using life cycle assessment. J. Biotechnol.

130:57–66.

Hofstetter, P., Braunschweig, A., Mettier, M., Wenk, R. M., and Tietje, O. 2008. The mixing

triangle: Correlation and graphical decision support for LCA-based comparison. J. Indus.

Ecol. 3:97–115.

Hoppenheidt, K., and Trankler, J. 1995. Biodegradable plastics and biowaste options for a common

treatment. Proceedings of the Biowaste ’95 Conference, Aalborg, Denmark, May 21–24.

Ishigaki, T., Sugano, W., Nakanishi, A., Tateda, M., Ike, M., and Fujita, M. 2004. The degradability

of biodegradable plastics in aerobic and anaerobic waste landfill model reactors. Chemosfere

54:225–233.

Kale, G., Auras, R., and Singh, S. P. 2007a. Comparison of the degradability of poly(lactide) pack-

ages in composting and ambient exposure conditions. Packaging Technol. & Sci. 20:49–70.

Kale, G., Kijchavengkul, T., Auras, R., Rubino, M., Selke, S., and Singh, S. P. 2007b. Composta-

bility of bioplastic packaging materials: An overview. J. Macromol. Biosci. 7:255–277.

Krueger, M., Kauertz, B., and Detzel, A. 2009. Life cycle assessment of food packaging made of

Ingeo biopolymer and (r)PET. Heidelberg, Germany: IFEU.

Patel, M. 2002. Life cycle assessment of synthetic and biological polyesters. Proceedings of the

International Symposium on Biological Polyesters, Munster, Germany, September 22–26.

Patel, M. 2005. Starch-Based Technology. In: Handbook of Biodegradable Polymers. Shrewsbury,

MA: Rapra Technology Limited, pp. 431–466.

Tokiwa, Y., and Calabia, B. P. 2006. Biodegradability and biodegradation of poly(lactide). Appl.

Microbiol. & Biotechnol. 72:244–251.

Weiss, M., Patel, M., Heilmeier, H., and Bringezu, S. 2007. Applying distance-to-target weighing

methodology to evaluate the environmental performance of bio-based energy, fuels, and

materials. Resour., Conserv. & Recycl. 50:260–281.

Widdecke, H., Otten, H., Marek, A., and Apelt, S. 2008. Bioplastics 07/08. Processing Pa-

rameters and Technical Characteristics, A Global Overview. CTC GmbH Fachhochschule

Braunschweig/Wolfenbuttel.

Zhang, J. Y., Beckman, E. J., Piesco, N. P., and Agarwal, S. 2000. A new peptide-based urethane

polymer: Synthesis, biodegradation, and potential to support cell growth in vitro. Biomaterials

21:1247–1258.

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