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Plastics contribute to several industrial activities, but they also cause environmental pollution. Additionally, they rely on an ever‐decreasing supply of natural, but non‐renewable, resources. Such plastics should be replaced by materials that are biodegradable and made from renewable resources such as polymers. They are synthesized from plant‐derived (R)‐3‐hydroxybutyric acid and l‐lactic acid meet these requirements. Most of the synthesized poly((R)‐3‐hydroxybutyrate‐co‐l‐lactate) with various monomer composition ratios were degraded by enzymes (PHB depolymerase or Proteinase K). Evaluation of biodegradability in activated sludge showed that copolymers with 80% or less of l‐lactic acid units were degraded. [ABSTRACT FROM AUTHOR]

We have previously reported that sequence-controlled copolyesters such as poly((ethylene diglycolate) terephthalate) (poly(GEGT)) showed higher melting temperatures than those of the corresponding random copolymers and high biodegradability in seawater. In this study, to elucidate the effect of the diol component on their properties, a series of new sequence-controlled copolyesters composed of glycolic acid, 1,4-butanediol or 1,3-propanediol, and dicarboxylic acid units was studied. 1,4-Butylene diglycolate (GBG) and 1,3-trimethylene diglycolate (GPG) were prepared by the reactions of 1,4-dibromobutane or 1,3-dibromopropane with potassium glycolate, respectively. Polycondensation of GBG or GPG with various dicarboxylic acid chlorides produced a series of copolyesters. Terephthalic acid, 2,5-furandicarboxylic acid, and adipic acid were used as the dicarboxylic acid units. Among the copolyesters bearing terephthalate or 2,5-furandicarboxylate units, the melting temperatures (Tm) of the copolyesters containing 1,4-butanediol or 1,2-ethanediol units were substantially higher than those of the copolyester containing the 1,3-propanediol unit. Poly((1,4-butylene diglycolate) 2,5-furandicarboxylate) (poly(GBGF)) showed a Tm at 90 °C, while the corresponding random copolymer was reported to be amorphous. The glass-transition temperatures of the copolyesters decreased as the carbon number of the diol component increased. Poly(GBGF) was found to show higher biodegradability in seawater than that of poly(butylene 2,5-furandicarboxylate) (PBF). On the other hand, the hydrolysis of poly(GBGF) was suppressed in comparison with that of poly(glycolic acid). Thus, these sequence-controlled copolyesters have both improved biodegradability compared to PBF and lower hydrolyzability than PGA. [ABSTRACT FROM AUTHOR]

Octamethylcyclam, tetramethylcyclam, cis-syn-cis-dicyclohexanocyclam, cis-anti-cis-dicyclohexanocyclam, cis-cyclohexanocyclam and trans-cyclohexanocyclam have reacted with nickel(II) (Ni2) ions contained in Ni(ClO4)2.6H2O to form their corresponding Ni2 cyclam complexes. The complexes have been subjected to magnetic susceptibility measurements, cyclic voltammetry and X-ray crystallographic studies to determine the spin states, half-wave potentials and crystal configuration that they exhibit. It has been determined that the alkyl substituents and the degree of congestion affect the structural and electrochemical properties of the complexes.

Previous studies on polyamide 4, excellent properties, functionalities, and biodegradation in natural condition have been shown. In this study, three‐branched (star‐shaped) copolyamides constituted of polyamide 4 and polyamide 6 constitutional unit were synthesized by anionic ring‐opening copolymerization of 2‐pyrrolidone with ε‐caprolactam. The thermal and mechanical properties and the biodegradability of the obtained copolyamides have been systematically investigated. The weight‐average molecular weight of the copolyamides was as high as tens of thousands (Mw 10–80 × 103 g/mol). The composition of the copolyamides was approximately in accord with the monomer feed ratio, thereby being controllable. The thermal and mechanical properties changed readily as the composition was varied (Tm 146–266°C, ΔHm 10–70 J/g, Td 278–369°C, tensile strength 28–64 MPa, elongation at break 80–750%). The copolyamide having 2‐pyrrolidone unit of 96–51 mol% exhibited biodegradability by an activated sludge. The biodegradation of the copolyamide proceeded uniformly without disproportion in constitutional unit. [ABSTRACT FROM AUTHOR]

Polyamide 4 containing an azo group (azo-PA4) was synthesized by the ring-opening polymerization of 2-pyrrolidone when 4,4′-azobiscyanopentanoyl chloride was used as an initiator. It was possible to control the molecular weight (MW) of the azo-PA4s through the concentration of the initiator to some extent, and the highest weight-average MW obtained was 35 × 103. To assess the initiation activity of the azo-PA4 for radical polymerization, styrene (St) was used as a vinyl monomer. The azo-PA4 was found to initiate the radical polymerization of St to produce polymers. Analyses by FT-IR spectroscopy, 1H-NMR, and differential scanning calorimetry after the homopolymers [polyamide 4 (PA4) and polystyrene (PSt)] were removed by Soxhlet extraction showed that the remaining polymer was PA4- block-PSt. Azo-PA4 was also found to have an initiation activity for other vinyl monomers (methyl methacrylate, vinyl acetate, etc.). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

4-Aminobutylic acid (GABA) is a monomer of plastic polyamide 4. Bio-based polyamide 4 can be produced by using GABA obtained from biomass. The production of L-glutamic acid (Glu) from biomass has been established. GABA is produced by decarboxylation of Glu in biological process. High-performance liquid chromatography (HPLC) with derivatization is generally used to determine the concentration of GABA and Glu in reacted solution samples for the efficient production of GABA. In this study, we have investigated the rapid determination of GABA and Glu by capillary electrophoresis-mass spectrometry (CE-MS) without derivatization. The determination was achieved with the use of a shortened capillary, a new internal standard for GABA, and optimization of sheath liquid composition. Determined concentrations of GABA and Glu by CE-MS were compared with those by pre-column derivatization HPLC with phenylisothiocyanate. The determined values by CE-MS were close to those by HPLC with pre-column derivatization. These results suggest that the determination of GABA and Glu in reacted solution is rapid and simplified by the use of CE-MS. [ABSTRACT FROM AUTHOR]

An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than −40 °C and melting temperature at 130–152 °C. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 °C. The triblock copolymers and PMPG homopolymer were found to show 9–15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications. [ABSTRACT FROM AUTHOR]

Poly(ester amide)s are attracting attention because they potentially have excellent thermal and mechanical properties as well as biodegradability. In this study, we synthesized a series of novel poly(ester amide)s by introducing γ-aminobutyric acid (GABA) regularly into polyesters, and investigated their properties and biodegradabilities. GABA is the monomer unit of biodegradable polyamide 4 (PA4). The new poly(ester amide)s were synthesized from the reaction of ammonium tosylate derivatives of alkylene bis(γ-aminobutylate) and p-nitrophenyl esters of dicarboxylic acids. All the obtained polymers showed relatively high melting temperatures (Tm). Their thermal decomposition temperatures were improved in comparison with that of PA4 and higher enough than their Tm. The poly(ester amide)s exhibited higher biodegradability in seawater than the corresponding homopolyesters. Their biodegradabilities in activated sludge were also studied. [ABSTRACT FROM AUTHOR]

In this article, the authors discuss various articles in this issue of the periodical on advanced polymer particles.