Biodegradable Plastics - August 2011
This month we're looking at the topic of biodegradable plastics.
The sheer volume of plastics waste that has been created over recent decades means that the subject of plastics disposal has been at the forefront of many people's minds for some time now. Biodegradable plastics offer a key solution, although there are many factors to consider, from the toxicity of end-products and the degradation mechanism, to the processability of the polymer and retention of form and function of the product throughout the expected lifetime. Although this issue is more widely know, biodegradable polymers are also playing critical roles in other areas, like medicine, pharmaceuticals (for example in drug delivery) and dentistry, where many of the same considerations apply.
With research going on into various bio-based and synthetic polymers, additives and fillers, new developments continue to be made for various end-use applications.
Abstracts
Please see below a selection of abstracts highlighted in the August Newsletter. These are records which relate to biodegradable plastics that have been recently added to the Polymer Library.
Click on the 7-digit accession numbers to find out about ordering a copyright-cleared full text copy of the items shown.
1087902 - BIODEGRADABLE POLY(GLYCOLIC ACID) NANOFIBER PREPARED BY CO2 LASER SUPERSONIC DRAWING
Synthesis of polyglycolic acid nanofibres, using drawing at supersonic velocities under the influence of carbon dioxide laser irradiation, is described. Fibres were examined using scanning electron microscopy and differential scanning calorimetry, and flow velocities were estimated using computer simulation. 27 refs.
Journal of Applied Polymer Science, 121, No.5, 15th Sept.2011, p.3078-3084, ISSN: 0021-8995, DOI: 10.1002/app.33982
Suzuki A; Shimizu R
1087413 - CONTROLLED RELEASE OF 5-AMINOSALICYLIC ACID (5-ASA) FROM NEW BIODEGRADABLE POLYURETHANES (Free Access to Full Text)
Segmented polyurethanes containing azo aromatic groups in the main chain were synthesised by reaction of 3,3'-azobis(6-hydroxybenzoic acid) (ABHB), 5-[4-(hydroxyphenyl)azo] salicylic acid (HPAS), and 5-[1-hydroxynaphthyl)azo] salicylic acid (HNAS) with hexamethylenediisocyanate (HDI). All synthesised monomers and polymers were characterized by elemental analysis, FTIR, 1H-NMR spectra, TGA and DSC analysis. All the synthesised azo polymers showed good thermal stability and the onset decomposition temperature of all these polymers was found to be above 195 degrees C under nitrogen atmosphere. The release of 5-ASA under physiological conditions (pH = 7.8 and pH = 1.5) was investigated at body temperature (37 degrees C). The release rate of 5-ASA increased with increasing pH (i.e., 7.8 > 1.5). 17 Refs.
Molecules, 15, No.4, 2010, p.2257-2268, ISSN: 1420-3049, DOI: 10.3390/molecules15042257
Kenawy E; Al-Deyab S S; El-Newehy M H
1087128 - ANALYSIS OF THE STRUCTURE-PROPERTIES RELATIONSHIPS OF DIFFERENT MULTIPHASE SYSTEMS BASED ON PLASTICIZED POLY(LACTIC ACID)
Poly(lactic acid) is one of the most promising biobased and biodegradable polymers for food packaging, an application which requires good mechanical and barrier properties. In order to improve the mechanical properties, in particular the flexibility, PLA plasticisation is required. However, plasticisation induces generally a decrease in the barrier properties. Acetyl tributyl citrate (ATBC) and poly(ethylene glycol) 300 (PEG), highly recommended as plasticisers for PLA, were added up to 17 wt% in P(D,L)LA. In the case of PEG, a phase separation was observed for plasticiser contents higher than 5 wt%. Contrary to PEG, the Tg decrease due to ATBC addition, modelled with Fox's law, and the absence of phase separation, up to 17 wt% of plasticiser, confirm the miscibility of PLA and ATBC. Contents equal or higher than 13 wt% of ATBC yielded a substantial improvement of the elongation at break, becoming higher than 300%. The effect of PLA plasticisation on the barrier properties was assessed by different molecules, with increasing interaction with the formulated material, such as helium, an inert gas, and oxygen and water vapour. In comparison to the neat sample, barrier properties against helium were maintained when PLA was plasticised with up to 17 wt% of ATBC. The oxygen permeability coefficient and the water vapour transmission rate doubled for mixtures with 17 wt% ATBC in PLA, but increased five-fold in the PEG plasticised samples. This result is most likely caused by increased solubility of oxygen and water in the PEG phase due to their mutual miscibility. To conclude, ATBC increases efficiently the elongation at break of PLA while maintaining the permeability coefficient of helium and keeping the barrier properties against oxygen and water vapour in the same order of magnitude. 41 Refs.
Journal of Polymers and the Environment, 19, No.2, June 2011, p.362-371, ISSN: 1566-2543, DOI: 10.1007/s10924-011-0285-5
Courgneau C; Domenek S; Guinault A; Averous L; Ducruet V
1086869 - BIODEGRADABLE WATER SOLUBLE COPOLYMER FOR ANTIMICROBIAL APPLICATIONS
Synthesis and characterisation of novel biodegradable, water soluble and optically active DL-malic acid (DMA) and citric acid (CA) copolymers were studied for possible use as antibacterial agents. The copolymers were synthesised by direct bulk melt condensation in the absence of a catalyst above 150 degrees C. Characterisation of obtained copolymers was carried out with the help of infrared absorption spectra, differential scanning calorimetry and thermo gravimetric analysis. The antibacterial activity of copolymers against bacteria was investigated. The results obtained shows the above copolymers possess a broad wound dressing activity against different types of bacteria and may be useful as antibacterial agents. 30 Refs.
Journal of Polymers and the Environment, 19, No.1, March 2011, p.225-229, ISSN: 1566-2543, DOI: 10.1007/s10924-010-0265-1
Mithil Kumar N; Varaprasad K; Ramachandra Reddy G; Siva Mohan Reddy G; Sivabharathi Y; Venkata Subba Reddy G; Venkata Naidu S
1085332 - BIODEGRADABLE POLYMERS SET TO SOAR (short article)
It is briefly reported that the next five years are likely to see the largest growth spike in the global biodegradable polymer market. According to BCC, by 2016 the market's value will have more than doubled from 932m pounds sterling to 2.5bn pounds sterling. The packaging sector accounted for 70% of total volume last year and while it will remain a major user of biodegradable polymers, this figure is expected to dip slightly to around 66% in five year's time. In value terms the packaging sector is worth 656m pounds sterling and should grow by around 20% (compound annually) to nearly 1.7bn pounds sterling by 2016. The use of biodegradable polymers in fibres and fabrics is set to grow from 134m pounds sterling in 2011 to 435m pounds sterling in 2016.
Plastics and Rubber Weekly, 24th June 2011, p.13, ISSN: 0032-1168
1084595 - BIODEGRADABLE PVOH-BASED FOAMS FOR PACKAGING APPLICATIONS
Biodegradable polyvinyl alcohol-based foams containing various amounts of recycled multilayer cartons composed of cellulose and LDPE were prepared by an environmentally friendly methodology. The effect of the recycled multilayer cartons on the microstructure, swelling behaviour, mechanical properties and thermal properties of the foams was examined and the relationship between the structure and properties of the foams studied. The foams were found to have a dual-pore structure consisting of large pores due to air entrapped during high-speed mixing in the polymer matrix and small pores due to water removal during freeze drying. 23 refs.
Journal of Cellular Plastics, 47, No.3, May 2011, p.271-281, ISSN: 0021-955X, DOI: 10.1177/0021955X11407401
Avella M; Cocca M; Errico M E; Gentile G
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