Poly (lactic acid) blends: Processing, properties and applications.

Polylactic acid blends: The future of green, light and tough

Understanding the basic properties of natural fibers is important to determine the optimal intended uses for instance as high-quality bio-composite raw material. This review describes the characteristics, and potential uses of some natural fibers in order to improve their sustainability and economic values. The natural fibers have low density and high strength to weight ratio and reduction make them potential as light weight composite and reinforcement materials. The microstructure and chemical compositions of fibers affect the mechanical properties with the fiber cross-sectional area is the most variable influencing the fiber strength. Natural fibers are easy to absorb water due to the presence of hemicellulose that give hydrophilic properties make them less compatible in the interaction with matrix with hydrophobicity properties. Higher cellulose content and crystallinity tend to result better strength properties of fiber while lignin is since versa. Besides that, fiber anatomical characteristics vary between different and same species that affect on the density and mechanical properties. The other factors namely environmental conditions, method of transportation, storage time and conditions, and fiber extraction affect the size and quality of the natural fibers.

A review on natural fibers for development of eco-friendly bio-composite: characteristics, and utilizations

A critical overview of publications on applications of supercritical fluids in polymer formation, modification and processing is presented. The review is focused on publications that appeared in 2014 only with the intent of providing an in-depth look at the activity in the most recent year to gain insights on the more recent trends and opportunities. The articles have been grouped under ten different application areas which include (1) polymer solutions and phase behavior, (2) polymerizations, (3) particle formation/micronization/drug delivery systems, (4) films, (5) fibers, (6) membranes, (7) nanocomposites, (8) porous materials – foams/scaffolds, (9) organogels, and (10) lignocellulosic polymers. In each category, articles are discussed under specific polymer or polymer type to better highlight those polymers that are receiving the greater level of attention. In 2014, more polymers were explored for their foamability, and for generation of nanocomposites. Poly(ɛ-caprolactone), poly(lactic acid) and poly(lactide-co-glycolide) were the most frequently investigated polymers for their porous matrix formation, or particle formation features using supercritical carbon dioxide because of their biomedical significance as biodegradable platforms for tissue engineering scaffolds and drug delivery devices. Poly(ethylene oxide), poly(lactic acid), and poly(methyl methacrylate) were the polymers that were explored in multiple application areas. Based on the close examination of these publications, the review provides specific observations on the advances that are made toward improved understanding of the factors that affect the miscibility of polymers in carbon dioxide, and for further understanding of the synergistic or other effects of components in polymer blends and composites, including the consequences of the presence of crystalline versus amorphous domains and morphological differences, or the consequences of the presence of nanofillers in different applications. New perspectives that are emerging in each application area are presented.

Supercritical fluids and polymers – The year in review – 2014

https://onlinelibrary.wiley.com/doi/pdf/10.1002/app.46265

Recent advances in core/shell bicomponent fibers and nanofibers: A review

Polylactide/TiO2 nanocomposites with different contents of nanoscale TiO2 were prepared by melt blending with a vane extruder in this work. SEM and TEM microphotographs indicate that the nanoparticles were well dispersed in the polymer matrix under the elongational flow field of the vane extruder. Crystallization and melting behavior were examined with DSC. The results show that TiO2 nanoparticles have an inhibition for the cold crystallization process of PLA to some extent and the cold crystallization temperature of nanocomposites shifted to a maximum value at about 106 °C with low TiO2 loadings (0.5 wt% or 1 wt%). Dynamic rheological measurements and TGA results show that the introduction of TiO2 has significantly improved the thermal stability. The toughness, surface wettability and UV resistance of the composites were also investigated in detail.

Preparation, characterization and properties of PLA/TiO2 nanocomposites based on a novel vane extruder

Thermal behavior, dynamic mechanical properties and rheological properties of poly(butylene succinate) composites filled with nanometer calcium carbonate

In this study, a typical immiscible system, a poly(lactic acid) (PLA)/polystyrene (PS) bioblend is used to investigate the effect of interface and phase structure on bubble nucleation and porous morphologies using supercritical carbon dioxide as a physical foaming agent. A unique microcellular skin-core structure with a porous core and surface, and a nonporous skin layer which is embedded in a solid PLA phase are observed. The involved possible mechanism of the interfacial nucleation and confined foaming behavior in multi-phase systems has been discussed. Because of the higher gas concentration and lower activation energy barrier, bubble nucleation preferentially occurs at the interface of the PS and PLA phases. Due to the constrained effect of the crystalline PLA phase, smaller space could be provided for the expansion of the PS phase during the foaming process, hence gas bubbles in the interior are restrained from further growth. The porous structures of the PS phases are similar when the blends have comparable phase morphology. The results indicated that the confinement effect on the foam behavior is not only related to the crystalline PLA phase but also the phase structure of the blend.

Unique interfacial and confined porous morphology of PLA/PS blends in supercritical carbon dioxide

Here we have obtained a thermoresponsive three-dimensional (3D) polyurethane (PU) sponge with temperature-controlled superwettability. First, silanization was used to enhance the surface roughness ...

Thermoresponsive Polyurethane Sponges with Temperature-Controlled Superwettability for Oil/Water Separation

Enhancing toughness of poly (lactic acid)/Thermoplastic polyurethane blends via increasing interface compatibility by polyurethane elastomer prepolymer and its toughening mechanism

Haichen Zhang

Papers

Preparation, characterization and properties of PLA/TiO2 nanocomposites based on a novel vane extruder

Thermal behavior, dynamic mechanical properties and rheological properties of poly(butylene succinate) composites filled with nanometer calcium carbonate

Unique interfacial and confined porous morphology of PLA/PS blends in supercritical carbon dioxide

Thermoresponsive Polyurethane Sponges with Temperature-Controlled Superwettability for Oil/Water Separation

Enhancing toughness of poly (lactic acid)/Thermoplastic polyurethane blends via increasing interface compatibility by polyurethane elastomer prepolymer and its toughening mechanism