POSS Fillers as a Factor Influencing on Viscoelastic Properties, Crystallization, and Thermo-Oxidative Degradation of Poly(Lactic Acid)-Epoxidized Natural Rubber PLA/ENR Blend

Magdalena Lipińska,Klaudia Toczek,Magdalena Stefaniak

doi:10.5772/intechopen.92595

Abstract

Polyhedral oligomeric silsesquioxanes (POSS) can be considered as the smallest silica particles that contain an inorganic cage-like silicon-oxygen structure surrounded by organic substituents. POSS are known to be reinforcing fillers able to enhance the fire retardancy and to increase the thermo-oxidative stability. The application of POSS with various functional groups and their effect on the properties of poly(lactic acid) (PLA) is analyzed based on the literature review. The influence of POSS with hydroxyl and glycidyl groups on the viscoelastic properties, crystallization, and thermo-oxidative degradation of PLA containing various contents of natural rubber ENR is discussed. The application of POSS with hydroxyl and glycidyl groups as an additive enhancing compatibility of PLA toughened by epoxidized rubber (ENR) is described. It is reported that POSS molecules with hydroxyl groups can enhance the thermo-oxidative stability of PLA melt.

Highlights

Nowadays polyhedral oligomeric silsesquioxanes (POSS) particles has received growing attentions as a new type of nanofillers used to prepare nanocomposites with enhanced thermal or mechanical properties [1, 2].POSS has hybrid organic-inorganic structure, and it can be considered as the smallest functionalized silica particle containing a cage-like silicon-oxygen inorganic core surrounded by organic groups
Incorporation of HO-POSS led to more homogenous morphology of the blend resulting in the enhancement of tensile strength as compared with 50 epoxidized natural rubber (ENR)/poly(lactic acid) (PLA) blend
Both incorporated POSS molecules influenced on the dynamic performance of the 50 ENR/PLA blend, decreasing the values of the storage shear modulus

Summary

Introduction

Nowadays polyhedral oligomeric silsesquioxanes (POSS) particles has received growing attentions as a new type of nanofillers used to prepare nanocomposites with enhanced thermal or mechanical properties [1, 2]. Wang et al [25] showed that octavinyl-POSS, and epoxycyclohexyl-POSS can act as nucleating agents, enhancing the crystallization ability of poly(lactic acid) in PLA/PBSA blends Both incorporated POSS increased the decomposition temperature retarding the thermal degradation of PLA/PBSA blends. Yu and Qiu [43] studied the crystallization behavior, spherulitic morphology, and crystal structure of poly(L-lactide) mixed via solution casting method with two different weight ratios (0.5, 1 wt%) of octavinyl-POSS Both the nonisothermal melt and cold crystallization of PLLA were enhanced by the presence of octavinylPOSS presence, to the higher degree of crystallinity χC = 44.4% for 1 wt% of octavinyl-POSS compared to χC = 8.0% for neat PLLA. Organic-inorganic hybrids with various arms’ length of poly(lactic acid) tethered with POSS synthetized via ring-opening polymerization of L-lactide were found to be nucleating additives increasing the degree of crystallinity of PLA [32, 33]. Octavinyl-POSS caused the opposite effect leading to the higher thermal stability and the delay in oxidation of PLA [45]

Materials and characterization

50 HO-POSS

Findings

Conclusions