Effect of starch/polylactic acid ratio on the interdependence of two-phase and the properties of composites

Abstract

Starch/polylactic acid (PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature (T g ), melting temperature (T m ) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature (T c ) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.

Plasticizer Enhancement on the Miscibility and Thermomechanical Properties of Polylactic Acid-Chitin-Starch Composites

“…The weight loss for samples A, B, C, D, and E started at 254 °C, 253 °C, 278 °C, 249 °C, and 247 °C respectively with maximum weight loss at 345 °C, 385 °C, 379 °C, 379 °C, and 385 °C. The lowered value of the onset temperature decreases with increase in starch content, and this has been reported by [18] and [26]. The thermal degradation behaviour of sample A and B look similar which shows domination of the chitin content, but above 312 °C, during the degradation, a slit difference was noticed…”

“…Sample E having the highest decomposition percentage can be traced to the characteristic of high starch content. Starch has been reported to improve the degradation behaviour of PLA [26,27]. Generally, the degradation is improved compared with pure PLA (sample F) and this could be as a result of starch or plasticizer, as reported by [27].…”

“…In their report, the tensile strength of the PLA composite increase with chitin content from 1% to 5% blending, but a drop is noticed in the composite with 10% reinforcement. Also, in the work of [26] on PLA-starch, an increase in tensile strength was reported with reduced starch content.…”

The impact of morphology on thermal properties and aerobic biodegradation of physically compatibilized poly (lactic acid)/co‐plasticized thermoplastic starch blends

“…The next step in weight loss was observed above 310°C because of the thermal degradation of the starch and the PLA chains. The presence of the only one decomposition peak below 400°C in DTG diagrams, which is reported as T max in Table , can be attributed to the high interdependency of TPS and PLA phases, pointing out the effectiveness of physical compatibilization approach for the preparation of PLA/TPS blends. Generally, the T max was increased by increasing PLA content in PLA/TPS samples, and eventually, 100PLA has the highest T max rather than others.…”

Improved Thermal Processing of Polylactic Acid/Oxidized Starch Composites and Flame-Retardant Behavior of Intumescent Non-Wovens

“…Therefore, significant progress in the development of bio-based polymers with renewable feedstock has generated great interest in the polymer industry [2]. Starch is one of the abundant biopolymers with diverse applications in many fields such as food processing, sizing material in textiles as binding agent to reduce friction and in vat dyes for the printing of 100% cotton fabrics by virtue of its cost effectiveness, biodegradability and renewability [3]. It consists of amylose and amylopectin.…”