Enhancement in Thermal Stability of Polyoxymethylene (POM)-Based Biopolymer Blend Materials

Jitlada Boonlertsamut,Atsushi Sakuma,Hiroyuki Hamada,Supaphorn Thumsorn,Toshikazu Umemura

doi:10.4236/msce.2019.77008

Abstract

In this study, we demonstrate the enhancement in thermal stability of polyoxymethylene (POM)-based biopolymer blend materials. Polyoxymethylene (POM)/Polylactic acid (PLA) blends have been used as alternative biopolymer materials for supporting environmental problems with thermal stability feature. The effects on POM biopolymer blend materials with a controlled PLA amount in their compositions under various injection conditions, were investigated by thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry. The POM/PLA biopolymer blend materials showed POM phase acted as a homogeneous nucleating site for increasing PLA crystallization, which improves storage modulus of the blend materials. The decomposition temperatures of POM/PLA biopolymer blends tend to shift around 30˚C - 50˚C lower compared to the decomposition temperatures of PLA. Thus, the decomposition temperature behavior of POM/PLA blends seems to be closer to POM. The suitable ratio in POM70/PLA30 resulted in the high strength of the blend materials. The POM/PLA biopolymer blend material was tested at various injection speeds and good miscibility was obtained at an injection speed of 100 mm/s. This enhancement of thermal stability in POM/PLA blend materials should be useful in the development of high-performance bio-based thermoplastic materials.

Highlights

This research focuses on the enhancement in thermal stability of POM biopolymer blend materials with controlled components in the compositions under varied injection conditions, where polyoxymethylene (POM) is selected as the main material
The POM/Polylactic acid (PLA) biopolymer blend material was tested at various injection speeds and good miscibility was obtained at an injection speed of 100 mm/s
While the Tm values of the PLA phase of POM70/PLA30 are approximately 165.47 ̊C, 165.59 ̊C, 165.52 ̊C, and 165.82 ̊C for injection speeds of 10 mm/s, 50 mm/s, 100 mm/s, and 1000 mm/s, respectively. These results indicate that the PLA content in POM70/PLA30 has no effect on the shifting of the Tm peaks of the blend materials

Summary

Introduction

This research focuses on the enhancement in thermal stability of POM biopolymer blend materials with controlled components in the compositions under varied injection conditions, where polyoxymethylene (POM) is selected as the main material. POM is a semi-crystalline engineering thermoplastic that has reported high stiffness, toughness, thermal, and dimensional stability [1] [2] [3]. It is interesting to study the individual component behaviors and mechanical and thermal properties of either miscible or partially miscible polymer blends. Polylactic acid (PLA) is classified as a biopolymer-based material and has advantageous properties such as high stiffness and strength but suffers from brittleness and low toughness [6] [7] [8]. It is possible to adjust POM-based blend materials by using properties of PLA content to get the desired performance. The designation of the compositions for the controllable thermal stability of PLA in the POM/PLA blends and the effects of injection speeds on the thermal properties were evaluated. The melt flow rates of POM and PLA are 10 g/10min at a temperature of 190 ̊C and a load of 2.16 kg, according to ISO 1133

Preparation of Specimens

Test Procedures

Results and Discussion

Conclusion