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Environmentally friendly poly(butylenesuccinate-co-butyleneazelate) (P(BS-co-BAz)s) aliphatic copolyesters with composition-dependent thermomechanical properties were synthesized from succinic acid (SuA), 1,4-butanediol (BDO), and dimethylazelate (DMAz) through a two-step polycondensation reaction. The molar SuA/AzA ratio was varied from 4:1 to 1:4, and the chemical structure and molecular characteristics of resulting (co)polyesters were characterized by NMR and SEC, whereas thermal properties and crystallinity were studied by differential scanning calorimetry (DSC), dynamic mechanical thermal analyses (DMTA), and X-ray diffraction (XRD). A good agreement between theoretical and experimental SuA/AzA molar ratios in the copolyesters was achieved, together with the recovery of semicrystalline random copolymers of uniform composition along the chains. NMR, DSC, DMTA, and XRD results show that depending on their composition the P(BS-co-BAz) copolyesters might find applications from elastomers to high-impact thermoplastics.

Carbon–carbon backbone polymers are non-biodegradable, persistent plastics that have accumulated on land and oceans due to human activities. They degrade and fragment into microplastics and smaller particle sizes but do not biodegrade at an acceptable and practical rate. Their continual buildup in the natural environment precipitates serious detrimental impacts on human health and the environment, as extensively documented in the literature and media. Nearly 77% of global plastics produced are carbon–carbon backbone polymers. More importantly, 90% of packaging plastics (153.8 million metric tons) are non-biodegradable, persistent carbon–carbon backbone polymers. The recycling rate of these non-durable packaging plastics ranges from 0 to 4%. Re-designing carbon–carbon backbone polymers to labile ester backbone biodegradable–compostable polymers and treating them along with biodegradable organic waste (such as food, paper, and organic wastes) in managed industrial composting is environmentally responsible. Diverting 1 million metric tons of biodegradable organic wastes in MSW bound for landfills and open dumps to industrial composting results in 0.95 million metric tons CO2 equivalents of GHG emissions reduction. This perspective paper discusses strategies and rationales regarding the redesign of carbon–carbon backbone polymer molecules. It describes the carbon footprint reductions achievable by replacing petro-fossil carbon with plant biomass carbon. Biodegradability and compostability are frequently used but misunderstood and misused terms, leading to misleading claims in the marketplace. This paper presents the fundamentals of biodegradability and compostability of plastics and the requirements to be met according to ASTM/ISO international standards. [ABSTRACT FROM AUTHOR]

An annular die is used to extrude cylindrical starch foams which are then sliced to yield foam sheets suitable for cushioning protection and insulation of shipping containers. Although starch foams, as a possible replacement of petroleum-based foams, have been prepared in the past, their sensitivity to humidity remained a problem. Extensive research in the last few years has been focused on resolving the collapse of the foam at high humidity, improve the cushioning protection, and develop an economical foaming process. However, these issues are still problematic and need to be resolved before such biobased foams can gain entry into the marketplace. In this study, a Box-Behnken statistical design of experiment was used to optimize the properties of foams extruded with various additives. It was found that the density, cell structure, and the rate of water penetration of these foams were affected by the feed rates (e.g., foam composition) of the water, talc, and poly(hydroxy ether) (PHE). The use of PHE was found to be extremely effective to minimize the water sensitivity and it significantly increased the water penetration time of the foam sheets. These starch foams efficiently absorb impacts and recover its physical shape quickly to provide multiple cushion protection for moderately delicate products. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Bio-based plastics, in which the fossil carbon is replaced by bio/renewable-based carbon, offer the intrinsic value proposition of a reduced carbon footprint and are in complete harmony with the rates and time scale of the biological carbon cycle. Identification and quantification of bio-based content is based on the radioactive C-14 signature associated with (new) biocarbon. Using experimentally determined biocarbon content values, one can calculate the intrinsic CO2 emissions reduction achieved by substituting petrocarbon with biocarbon—the material carbon footprint value proposition. The process carbon footprint arising from the conversion of feedstock to final product is computed using life-cycle assessment methodology. Biodegradability in conjunction with selected disposal systems such as composting and anaerobic digestion offers an end-of-life solution to completely remove the plastic substrate from the environment. Not all bio-based polymer materials are biodegradable, and not all biodegradable polymers are bio-based. Most importantly, complete biodegradability (complete utilization of the polymer by the microorganisms present in the disposal environment) is necessary as per ASTM and ISO standards, otherwise there could be serious health and environmental consequences. [ABSTRACT FROM PUBLISHER]

Polylactic acid (PLA) has been modified by electron beam radiation in the presence of glycidyl methacrylate (GMA) to enhance the melt strength of PLA. The modified PLA was prepared by varying both the amount of GMA and the irradiation dose and was characterized by observing the thermal properties, the melt viscoelastic properties and the gel fraction. For comparison, virgin PLA was also irradiated. All irradiated virgin PLA had a lower complex viscosity and a storage modulus compared to virgin PLA due to irradiation-induced chain scission. However, these properties were remarkably improved due to formation of long chain branching and retarding chain scission if GMA was introduced in this system. The increase in melt viscoelastic property was much dependent on the irradiation dose. At optimum doses of radiation, it showed maximum complex viscosity and storage modulus. The PLA irradiated with 20 kGy in the presence of 3 phr GMA showed a complex viscosity of about 10 times higher and a storage modulus of 100 times higher than those of virgin PLA at 0.1 rad/s. Gel fraction measurement revealed that chain scission and branching was more dominant than crosslinking. The biodegradability of irradiated PLA was slightly decreased by the presence of GMA. [ABSTRACT FROM AUTHOR]

The article discusses the incorporation of starch into plastic materials in order to create environmentally-friendly and biodegradable products while maintaining plastics performances. The authors examine the use of maleated thermoplastic starch (MTPS) in extrusion melt-blending in blown-film applications. MTPS is melt-blended with poly(butylene adipate-co-terephthalate) (PBAT), the article states. Topics include an increased interfacial area for grafting reactions and formations of graft copolymers generated by acid-promoted transesterification reactions.

The article discusses on the extrusion polymerization process to manufacture three-arm polyϵ-caprolactone polymers. It was found that a screw configuration composed of conveying elements was effective for the polymerization process. Higher conversions were produced by monomer with a lower amount of free acids. in an increasing temperature, average residence time did not change but it decreased from 2.4 to 2 minutes when the screw speed was increased in the polymerization of monomer.

Describes the synthesis of melt-stable and semicrystalline PPDX chains through a fast continuous single-step process conducted in a co-rotating intermeshing twin-screw extruder. Performance of reactive extrusion; Calculation of molecular weight distribution; Thermal stability of PPDX.

Abstract: Life cycle assessments of bio-based polymer resin and products historically have shown favorable results in terms of environmental impacts and energy use compared to petroleum-based products. However, calculation of these impacts always depends on the system and boundary conditions considered during the study. This paper reports a cradle-to-cradle Life Cycle Assessment (LCA) of poly(lactic acid) (PLA) in comparison with poly(ethylene terephthalate) (PET) and poly(styrene) (PS) thermoformed clamshell containers, used for packaging of strawberries with emphasis on different end-of-life scenarios. It considers all the inputs such as fertilizers, pesticides, herbicides and seed corn required for the growing and harvesting of corn used for manufacturing PLA. For PET and PS, the extraction of crude oil and the entire cracking processes from crude oil through styrene and ethylene glycol and terephathalic acid are considered. Global warming, aquatic acidification, aquatic eutrophication, aquatic ecotoxicity, ozone depletion, non-renewable energy and respiratory organics, land occupation and respiratory inorganics were the selected midpoint impact categories. The geographical scope of the study reflects data from Europe, North America and the Middle East. PET showed the highest overall values for all the impact categories, mainly due to the higher weight of the containers. The main impacts to the environment were the resin production and the transportation stage of the resins and containers. This implies that the transportation stage of the package is an important contributor to the environmental impact of the packaging systems, and that it cannot be diminished. [Copyright &y& Elsevier]

Abstract: This contribution aims at reviewing how reactive extrusion (REx) technique can participate in the design and development of biodegradable polymeric materials more particularly based on aliphatic polyesters issued from both renewable (agrochemical) and fossil (petrochemical) resources. On one side, REx will be approached for producing in a continuous way biodegradable aliphatic polyesters by ring-opening polymerization of lactones. Tin and aluminum-based catalysts will be considered for quantitatively converting the cyclic monomer in high molecular weight polyester chains within residence time of a few minutes only. On the other hand, such polyesters will undergo various chemical modifications again performed by REx. Self-branching reactions will be investigated in order to compensate the characteristic molecular weight reduction of the polyester chains as triggered by hydrolysis and/or transesterification side-reactions. Controlled functionalization reactions by maleic anhydride treatment will be studied as well. Finally biodegradable composite materials will be produced by REx and will rely upon the interface compatibilization between the polyester matrix and natural fillers such as starch granules or talc microparticles. To cite this article: J.-M. Raquez, et al., C. R. Chimie 9 (2006) . [Copyright &y& Elsevier]