Blends of poly(L-lactide) (PLA), containing from 5, 15, or 25 wt % potato starch, unmodified or hydrophobized in methane plasma, were prepared and studied. To enhance the drawability of the blends, the plasticization of PLA with 10 wt % poly (ethylene glycol) (PEG) was also employed. The thermal and mechanical properties of the blends with amorphous and crystalline matrices were investigated. The hydrophobization of starch did not improve the ultimate properties of the blends, which were generally worse than those of neat PLA, because of the separation of the starch grains from the polymer matrix during tensile drawing. The separation also occurred in blends with a PEG-plasticized matrix containing 15 wt % modified starch, which fractured earlier than PLA plasticized with PEG. Nevertheless, the elongation at break of the plasticized blends reached 1.3, which was considerably more than that of blends with corresponding starch contents without a plasticizer (ca. 0.05).

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An experimental study on the influence of chain extender (CE) on the properties and foamability of two grades of polylactide (PLA) has been carried out. The influence of CE on the polymer crystallinity and viscoelastic properties that are critical during the foaming process was investigated. After addition of CE an increase in the viscosity and the cold crystallization temperature of PLA was observed. Selection of PLA grade has been correlated with a structure of the polymer. The cellular structure of PLA was obtained during extrusion process using the chemical blowing agent. The addition of 1.0 and 1.5 % CE caused fine cellular structure and low density (0.7 g/dm 3 ) of foamed PLA.

Linking place attachment and social interaction: towards meaningful public places ABSTRCT Purpose : A public space is a place of significance when it fulfils the human need for social interaction and attachment. However, the scarcity of public spaces poses a challenge to support socialisation for people within a defined social and cultural group. The purpose of this paper is to explore the association between place attachment and social interaction within public spaces in the city centre of Kuala Lumpur, Malaysia. Design/methodology/approach: Face-to-face interviews with urban users were conducted to examine the users' engagement in three main public spaces in the city and the significance of these spaces to everyday social interaction. Field observations were carried out to examine patterns of users' activities and interactions. Findings: The authors uncover a lack of multi-functional spaces to support diverse forms of interactions in the city. A street has an important function to generate activities. However, spaces for people to sit and stay remain scarce, and are in most cases consumed by extended commercial use and thus considered private. Opportunities for social interaction are very limited. The significance of the places relates strongly to commercial and tourism functions, and hence place attachment evolves around those activities. Participants associated their familiarity and engagement with interaction between familiar people, close ethnic relationships and business acquaintances. Practical implications: The authors argue that more robust and socially responsive public spaces should be reclaimed for the culturally diverse users. Social implications: Development of attachment through meaningful spaces for people to stay and interact could enhance the role of public spaces in the city. Originality/value: By understanding the social meanings of places, particularly in a multi-cultural setting, a stronger basis for designing and managing urban places towards resiliency and social sustainability can be provided.

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In this study, property changes of controlled aged LDPE/feather composites in comparison to those of nonaged samples were investigated by mechanical tests, dynamic rheological and thermal tests, infrared spectroscopy, and oxygen permeability analysis. The viscoelastic behavior of the aged composites was modified, whereas a pseudoplastic character was observed for the nonaged samples. After weathering, infrared spectroscopy indicated the formation of carbonyl and vinyl groups, and the oxygen permeability became significantly higher than for the reference samples. DSC results showed α-helix denaturation of keratin after aging and an increase in crystallinity due to reinforcement of composites containing feather fibers upon UV exposure. An aging time of 500 h was found to induce surface degradation of composites, especially for a feather fiber loading of 10 wt %.

The morphology, rheology, and mechanical properties of blends of polysulfone (PSF) with up to 65% of a wholly aromatic liquid crystalline polymer (LCP) were investigated. In injection molded specimens a skin-core morphology was observed with the LCP minor phase oriented in the skin and globular in the core. Scanning electron microscopy of fractured surfaces showed sharp phase boundaries, suggesting low interfacial adhesion. The neat PSF and blends with low amounts of LCP exhibited a low shear Newtonian plateau not observed in the blends with high LCP levels. The addition of LCP to PSF resulted in an increase in stiffness, a small increase in tensile strength, and a significant improvement in processability.

ABSTRACT:The mechanical properties, melt rheology, and morphology of binary blends comprised of two polypropylene (PP) grades and two liquid crystalline polymers (LCP) have been studied. Compatibilization with polypropylene grafted with maleic anhydride (PP-g-MAH) has been attempted.A moderate increase in the tensile moduli and no enhancements in tensile strength have been revealed. Those findings have been attributed to the morphology of the blends, which is predominantly of the disperse mode. LCP fibers responsible for mechanical reinforcement were only exceptionally evidenced. Discussion of PP-LCP interfacial characteristics with respect to mechanical properties-morphology interrelations allowed evaluation of the compatibilizing efficiency of PP-g-MAH. Factors important for successful reinforcement of PP with LCP have been specified.