Poly commercial composting

Commercial poly(butadiene), which is mainly the 1,4 isomer, is also used to improve the impact resistance of polystyrene (Chapter 1). Polydienes also increase the rate of physical disintegration of polyblend containing them. The addition of a styrene-butadiene block copolymer e.g. SBS, page 9 et seq.) to polyethylene also accelerates the peroxidation of the latter. However, this system also requires a polymer-soluble transition metal ion catalyst e.g. an iron or manganese carboxylate) to increase the rate of photooxidation in the environment by the reactions shown in Scheme 5.3. The products formed by breakdown of alkoxyl radicals (PO ) (Scheme 3.4) are then rapidly biodegradable in compost (page 107 et seq.). 

A comparison of the properties of materials is made to indicate a potential replacement of existing materials with emerging, commercially available renewable, compostable alternatives. The analysis is limited to products that are commercially available, e.g., starch, cellulose, whole crop polymers, and polyesters such as poly(lactic acid) (PLA), poly(hydroxyalkanoate), and others (5). Commodity plastics used in food packaging are summarized in Table 7.1. 

Poly(lactic acid) (PLA) is a thermoplastic polyester characterized by mechanical and optical properties similar to polystyrene (PS) and polyethylene terephthalate (PET). It is obtained from natural sources, completely biodegradable and compostable in controlled conditions as already stated in previous chapters. PLA offers some key points with respect to classic synthetic polymers, since it is a bioresource and renewable, while raw materials are cheap and abundant compared to oil. From a commercial point of view, a non-secondaiy approach, it can embellish with the word green so fashioned for the major stream consumers. Legislation can also help the commercial diffusion of biopolymers. As an example, a decisive leap has been made with the control of non-biodegradable shopping bags distribution in the European Commission and many of its member states. In addition, PLA has received some interest from the industrial sectors because of its relatively low price and commercial availability compared with other bioplastics. This is the veiy key point for any successful polymer application. In fact, the current price of commercial PLA falls between 1.5 and 2 kg , which is sufficiently close to other polymers like polyolefins, polyesters or poly(vinyl chloride) (PVC). Clearly, the PLA market is still in its infancy, but it is expected that the decrease in the production costs and the improvement in product performance will result in a clear acceleration in the industrial interest for PLA uses. It is estimated that PLA consumption should reach... 

A continuous increase in oil prices and environmental concerns about the use of common petroleum-based plastics have recently led to a growing interest in bio-based plastics. Poly(lactic acid) (PLA), a plastic derived from fermented plant starch, is fast becoming one of the popular alternatives to traditional petroleum-based plastics. Even though PLA has been known for more than a century, it has only been used commercially in recent years in a number of biocompatible/ bioabsorbable biomedical device market, packaging applications, and so on. A number of factors contribute to the success of PLA in these applications, including its physical properties as well as favorable compostable and degradation characteristics [1]. 

PLA Poly(lactic acid) commercial sample from Mitsui Chemicals Composting (ISO 14855-1, ISO 14855-2, enzymatic degradation) CO2 evolution measurement based on titration and gravimetric methods Biodegradation of PLA powder was 91% for 31 days (ISO 14855-1 method) and 80% for 50 days at 58°C (ISO 14855-2 method) Cellulose powder was used as reference material PLA in the form of powders of different size was used [17]... 

PLA Poly(lactic acid) commercial bottles and deh containers Composting under real conditions (compost pile temp. 65°C moisture 63%, pH 8.5) visual inspection molecular weight changes (GPC method) glass transition and melting temperature (DSC method) decomposition temperature (TGA method). Degradation of PLA containers <30 days under composting conditions [26]... 

BAK 1095, commercial polyesteramide based on caprolactam, butanediol and adipic acid was fonnd to be completely biodegradable according to German compostability standard DIN 54900 [113], Biodegradability of laboratory synthesized poly(esteramide) was studied in the controlled composting test according to EN 14046 standard [114], It was found that poly(esteramide) meets the biodegradation criteria of the standard. 

The majority of petroleum-based compostable plastics belong to the polyester family, including Ecoflex , polycaprolactone (PCL), Ecovio , poly-butyrate adipate terephthalate (PBAT), and aliphatic copolyesters (The Impacts of Degradable Plastic Bags in Australia 2003). Table 4.14 lists several commercially available biodegradable or compostable plastic products. 

Renewable sources such as starch-made PLAs are biodegradable and compostable. They usually have very low or no toxicity but possess high mechanical performance compared to those of commercial pol5miers. However, the thermal stability of PLAs is not sufficiently high enough to use them as an alternative in many commercial pol5nner applications. Various PIA hlends have been studied to improve their thermal properties. A stereocomplex is formed from enantiomeric PLAs, poly(L-lactic acid) (PLIA), and poly(D-lactide) (PDLA) due to the strong interaction between PLLA and PDLA chains. 

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