Search

Aiming at the tuning of thermo-mechanical features by chemical cross-linking, a biopolyester commercial blend based on poly(lactic acid) (PLA) with poly(butylene adipate-co-terephthalate)(PBAT) (ecovio®T2280, BASF) was processed in Brabender in the presence of dicumyl peroxide (DCP, 0-0.2 wt.-%). The effect of DCP addition was investigated and rationalized by means of solubility tests and gel content evaluation, as well as rheological, mechanical, and molecular weight analysis of the prepared compounds. Moreover, detailed DSC and TMDSC investigations provided a deep insight into the structural modifications occurred at the macromolecular level. We found that chain branching as well as cross-linking occurred in the samples processed in the presence of DCP, thus returning compounds having increased toughness and modulated crystalline content and thermal behavior. Noteworthy, the presence of specific, undisclosed additives, triggers the occurrence of peculiar behaviors in the ecovio® commercial blend, not previously observed in model PLA/PBAT blends of similar composition. Despite only partially soluble in chloroform, the new ecovio® DCP-modified compounds still remained workable in the melt, thus providing a suitable, simple and economically affordable strategy to finely modulate the thermo-mechanical properties starting from a commercially available, compostable compound. [ABSTRACT FROM AUTHOR]

Molecularly designed materials based on macromolecules and organic dyes offer unique opportunities in connection with the possibility of preparing optically responsive 'smart' materials. Indeed macromolecules are able to transmit and amplify small signals reaching sites at interacting distance through the involvement of the whole chain. The corresponding materials can then acquire stimuli-responsive properties in relation to specific features connected to primary structure and conformation. As a first approach to benefit from the above features for preparing eco-compatible smart materials, bio-related polypeptides, polysaccharides and polyesters can be used as the macromolecular partner in combination with a selected dye following different interaction methodologies. Two distinct routes were used to prepare optically responsive products from the above bio-related polymers, respectively based either on the covalent bonding to the original macromolecules of photochromic molecular species, such as azobenzene and spiropyran, or on the morphology-modulated dispersion of highly conjugated dyes in the polymer bulk. Examples related to the two different routes have been investigated in our laboratory and are presented and discussed also with reference to selected recent cases from the literature. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The article examines the modulation of poly(lactic acid) (PLA) properties as a consequence of poly(butylene adipate-co-terepthalate) (PBAT) blending and acetyl tributyl citrate (ATBC) plasticization. The researchers evaluated the effect of the concentration of either the plasticizer or copolyester on the final material flexibility of the PLA. The study analyzed the preferential solubilization of ATBC in the PBAT phase and assessed the possible use of PLA in food packaging applications.

Front Cover: Processing of PLA/PBAT compostable blends with dicumyl peroxide gives chain‐branching and crosslinking, thus providing a simple and economically affordable strategy to finely modulate the thermo‐mechanical properties of the commercial material. Further details can be found in the article by F. Signori,* A. Boggioni, M. C. Righetti, C. E. Rondán, S. Bronco, and F. Ciardelli on page 153. [ABSTRACT FROM AUTHOR]