Polymer blend

About: Polymer blend is a research topic. Over the lifetime, 18474 publications have been published within this topic receiving 437183 citations. The topic is also known as: polymer mixture & Polymerblend 或者 Polyblend.

Preparation and characterization of thermoplastic starch/pla blends by one step reactive extrusion

Abstract: In the presence of dicumyl peroxide, the compatibility of thermoplastic dry starch (DTPS)/poly(lactic acid) (PLA) blends, using maleic anhydride (MA) as compatibilizer, was investigated. The plasticization of starch and its compatibilizing modification with PLA was accomplished in a single-screw extruder by one-step reactive extrusion. In the presence of MA, the plasticization of starch in DTPS/PLA blends could be improved and homogeneous DTPS/PLA blends could be achieved as observed using scanning electron microscopy. Tensile tests showed that the tensile strength of compatibilized DTPS/PLA blends was about 40.5 MPa higher than that of the original composites. Differential thermal analysis indicated that the glass transition temperature of DTPS and PLA became closer in the presence of MA than the blend without any additions, which suggested the compatibility between DTPS and PLA was improved. In addition, Fourier transform infrared spectroscopy proved that MA improved the interaction between DTPS and PLA. At the same time, the blend became more thermally stable as shown by thermogravimetric analysis results. A novel decomposition peak at about 450 °C was detected in the compatibilized blend, which was higher than those observed for DTPS and PLA. Finally, a rheological study suggested that MA could improve the fluidity of DTPS/PLA blends. Copyright © 2007 Society of Chemical Industry

Biodegradable polymer films and sheets suitable for use as laminate coatings as well as wraps and other packaging materials

Abstract: Biodegradable polymer blends suitable for laminate coatings, wraps and other packaging materials manufactured from at least one 'hard' biopolymer and at least one 'soft' biopolymer. 'Hard' biopolymers tend to be more brittle and rigid and typically have a glass transition temperature greater than about 10 °C. 'Soft' biopolymers tend to be more flexible and pliable and typically have a glass transition temperature less than about 0 °C. While hard and soft polymers each posses certain intrinsic benefits, certain blends of hard and soft polymers have been discovered which possess synergistic properties superior to those of either hard or soft polymers by themselves. Biodegradable polymers include polyesters, polyesteramides and thermoplastically processable starch. The polymer blends may optionally include an inorganic filler. Films and sheets made from the polymer blends may be textured so as to increase the bulk hand feel. Wraps will typically be manufactured so as to have good 'dead-fold' properties so as to remain in a wrapped position and not spring back to an 'unwrapped' and planar form. Laminate films will typically have good water vapor barrier properties as measured by their Water Vapor Permeability Coefficient (WVPC).

Improvement in mechanical properties of reinforced thermoplastic elastomer composite with kenaf bast fibre

Abstract: This paper report on the development of thermoplastic elastomer composite reinforced with 20 vol.% kenaf fibre. Two types of impact modifier were blended with polypropylene (PP) namely; thermoplastic natural rubber (TPNR) and polypropylene/ethylene–propylene–diene–monomer (PP/EPDM). Both composites were produced via double melt blending method using Haake internal mixer before they were compression moulded. The ratio of thermoplastic:elastomer was 70:30 for both polymer blends. Due to incompatibility between matrix and reinforcement, maleic anhydride polypropylene (MAPP) was added as in the case of treated composite. It was found that the tensile strength for TPNR is about 12% higher than the PP/EPDM matrix. The present of kenaf fibre (KF) and MAPP however has significantly increased the tensile strength of the PP/EPDM composite by approximately 81% while only 55% increment attained in TPNR–KF–MAPP as compared to unreinforced TPNR. Apart from that, flexural properties and impact strength are greatly improved for treated kenaf fibre composite. This shows that KF has imparted its tensile strength to the PP/EPDM system with good interaction provided by the compatibilizer agent. Scanning electron micrographs (SEMs) revealed that the improvement achieved in mechanical properties was due to the interaction between both matrix systems and kenaf fibre.

Starch-based biodegradable blends: morphology and interface properties

Abstract: In order to improve the properties of plasticized wheat starch (PWS) and to conserve its final biodegradability, PWS can be blended with biodegradable polyesters [polyesteramide, poly(e-caprolactone), poly(lactic acid), poly(butylene succinate adipate) and poly(butylene adipate terephthalate)] which exhibit variable polar characteristics. This paper is focused on the analysis of the compatibility of these blends which vary according to their formulation. To understand the lack of affinity between the different phases, interface adhesion has been investigated by contact angle measurements to obtain the work of adhesion. From these determinations a forecast approach has been developed to predict blend compatibility. Blend structures were obtained by scanning electron microscopy observations. Blends show either a dispersed structure or a co-continuous morphology. Percolation thresholds (co-continuity) and full continuity regions were determined thanks to a method based on solvent extraction. Finally, rheological investigations have been carried out on the different biodegradable polymers to understand better the blend structure formation during the process. Copyright © 2004 Society of Chemical Industry