Thermoplastic starch/PVAl compounds: Preparation, processing, and properties

Abstract

ABSTRACT:As a renewable and native polymeric material, thermoplastic starch is gaining increased acceptance because of resource and environment concerns. This study reports the formulation design of native starch/polyvinyl alcohol (PVAl) compounds; the preparation technology to make them available for thermoplastic processing; and their rheological, mechanical, and degradation properties. Among various plasticizers investigated, a mixture of glycerin and water (50/50 wt %) is found to be the best one for the compounds in terms of rheological behavior, mechanical properties, and environmental stability. The mechanical properties do not increase with the PVAl content to an expected extent, mainly due to the poor interface adhesion between the fibrous PVAl structure and the starch matrix.

Recent advances in starch, polyvinyl alcohol based polymer blends, nanocomposites and their biodegradability

“…The conventional plasticizer used for starch and PVOH composites is glycerol and water (Lawton & Fanta, 1994;Liu, Feng, & Yi, 1999), but several other chemicals like sorbitol (Park, Chough, Yun, & Yoon, 2005;Westhoff, Kwolek, & Otey, 1979), urea (Tudorachi, Cascaval, Rusu, & Pruteanu, 2000), citric acid (Park et al, 2005;Zou, Jin, & Xin, 2008), as well as complex plasticizers (Zhou, Cu, Jia, & Xie, 2009) have also been successfully employed. Liu et al (1999) compounded starch and PVOH using a single screw extruder.…”

“…Liu et al (1999) compounded starch and PVOH using a single screw extruder. To obtain good processability, they found that glycerol is much more effective than water as a plasticizer for the compounds, but it scarified tensile strength and water barrier properties.…”

“…They attributed this property deterioration to the relatively poor compatibility between starch and PVOH. Liu et al (1999) also found that incorporation of PVOH into starch could enhance the mechanical properties, but such improvement was very limited, mainly due to the poor interface adhesion between the fibrous PVOH structure and the starch matrix. Another problem with starch-PVOH blends is their poor water barrier properties.…”

Study of the Plasticizer Effect and Characterization on Diverse Pseudo-Thermoplastic Starch Biodegradable Films

“…To improve the thermal processing of starch, the addition of plasticizer is an effective way to weaken the hydrogen bonding interactions of starch molecules, increase the molecular mobilities, reduce the melting temperatures, and modify basic starch into pseudo-thermoplastic starch (PTS) [7][8][9] .…”

The Preparation and Characterization of Glycerol Pseudo-Thermoplastic Starch/Glycerol Pseudo-Thermoplastic Polyvinyl Alcohol (GTPS/GTPVA) Biodegradable Films Using the Solution Casting Method

“…The developments on the production of starch=PVA blended biodegradable polymers have been reported by several authors [7][8][9][10][11][12] . The blended materials could be produced into excellent mechanical and biodegradable polymers, but the materials are not sufficiently melted by melt processing.…”