Hydrophobic Thermoplastic Starches Modified with Polyester-Based Polyurethane Microparticles: Effects of Various Diisocyanates

Abstract

It is critical to prepare ductile and hydrophobic modified starch material in an effective and environmentally friendly way. In this work, polyurethane prepolymers (PUPs) with various isocyanates were synthesized and mixed reactively with thermoplastic starches (TPS) in an intensive mixer to prepare modified TPS. The effects of the isocyanates on the structure and properties of the modified TPS were then investigated by using scanning electron microscope (ESEM), tensile tester, and contact angle meter. Results showed that mechanical properties of the modified TPS were improved with the increase in hydrophobicity of the isocyanate. 4,4 0 -Methylenedi-p-phenyl diisocyanate (MDI) was hydrophobic, the NCO groups in PUPs were not easily consumed by water when modified starch was prepared, leading to a significantly increased reaction of the NCO groups with starch. As the amount of urethane bonds between starch and PUP increased, the compatibility between the two polymers was also improved, resulting in the improvement of tensile properties. Isocyanates played an important role in improving the compatibility between the starch and PUP and the properties of the modified TPS.

Preparation and properties of compatible starch-polycaprolactone composites: Effects of hard segments in the polyurethane compatibilizer

“…Additionally, it has been found that the flexibility of aliphatic HDI-or IPDI-based hard segments favor micro-phase separation in segmented polyurethanes while the rigidity of the aromatic TDI-or MDI-based hard-segments hinder micro-phase separation [40]. Subsequently, our research team has reported in previous studies [41,42] that the structure and properties of starch modified with polyurethane were directly affected by the molecular weight of the soft segment as well as the type of the isocyanates used in preparing the PUP. Therefore, in order to build a theoretical basis for the preparation of starch-PCLPU-PCL composites that exhibit exceptionally favorable performance, our research team further investigated the impact of the molecular weight of the polyurethane soft segments on the interface structure and properties of starch-PCLPU-PCL composites.…”

Influence of addition of silanized nanosilica and glycerol on hydrophobicity of starch using a factorial design

“…The search for new polymeric materials, mainly the ones that derivate from renewable sources, has been the reason for the realization of diverse studies [1][2][3][4] . A material with promising potential for that end is the starch, for its raw material is very accessible in many parts of the world.…”

“…A material with promising potential for that end is the starch, for its raw material is very accessible in many parts of the world. Besides that, in general, it is obtained with low costs, being used at the formation of blends or composites with polymeric materials [1][2][3][4][5][6] .…”

Structures and properties of polycarbonate modified polyether‐polyurethanes prepared by transurethane polycondensation

“…A substantial effort has gone into improving the mechanical properties and water resistance of polyether‐PUs (PEPUs) without significantly sacrificing the molecular weights and optical properties by utilizing a diol mixture of a polyether polyol and a polycarbonate polyol as soft segments . Comparison of the properties of two series of thermoplastic PU elastomers, poly(propylene glycol) (PP)‐based PU (PPPU) samples and poly(oxytetramethylene) glycol (PTMG)‐based PU (PTPU) samples, were conducted by Kim et al .…”