Solid and microcellular polylactide nucleated with PLA stereocomplex and cellulose nanocrystals
- PDF / 2,817,515 Bytes
- 19 Pages / 595.276 x 790.866 pts Page_size
- 107 Downloads / 151 Views
Solid and microcellular polylactide nucleated with PLA stereocomplex and cellulose nanocrystals Martin Boruvka1 · Lubos Behalek1 · Petr Lenfeld1 · Pavel Brdlik1 · Jiri Habr1 · Sorasak Wongmanee2 · Jiri Bobek3 · Miroslava Pechociakova4 Received: 29 August 2019 / Accepted: 19 February 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract Blending polylactide (PLA) with poly(d-lactide) (PDLA) and cellulose nanocrystals (CNC)-based stereocomplex (SC) nanohybrids presents practical approach to produce fully biobased blends and nanocomposites with enhanced properties. This paper investigated the nucleation effect of PLA/PDLA and PLA/PDLA-g-MAH/CNC nanohybrids at low loading levels on the non-isothermal crystallization, morphology, as well as thermal and thermo-mechanical properties of PLA-based samples. Neat PLA, blends and nanocomposites were produced by conventional and microcellular injection molding. Nitrogen (N2) in a supercritical state was used as the physical blowing agent for preparation of microcellular samples. CNC-based SC showed superior nucleating efficiency compared to SC nucleating agents. However, low mold temperature resulted in relatively low degree of crystallinity (~ 15%). In addition, decrease in cell size and increase in cell density of microcellular samples have been observed after introduction of both nucleating agents. Slight increase in mechanical properties of nucleated samples compared to neat PLA has been ascribed to the higher degree of crystallinity. Despite these, decrease in all mechanical properties of microcellular samples has been noticed when compared to solid counterparts. Furthermore, dynamic mechanical analysis (DMA) reveals subsequent foaming and dramatic decrease in dimensional stability of microcellular samples above glass transition temperature (Tg). The storage modulus in a glassy region has been improved in both solid blends and nanocomposites. In addition, shift of Tg due to restricted chain mobility of PLA due to retarded relaxation of amorphous regions due to SC interactions has been observed. Keywords Biocomposites · Microcellular injection molding · Cellulose nanocrystals · Poly (lactic acid) · Stereocomplex
Introduction
* Martin Boruvka [email protected] 1
Department of Engineering Technology, Faculty of Mechanical Engineering, Technical University of Liberec, Liberec, Czech Republic
2
Department of Mechanical Engineering Technology, College of Industrial Technology, King Mongkut’s University of Technology North Bangkok, Bangkok, Thailand
3
Laboratory of Advanced Industrial Technologies, Institute for Nanomaterials, Advanced Technologies and Innovation, Liberec, Czech Republic
4
Department of Material Engineering, Faculty of Textile Engineering, Technical University of Liberec, Liberec, Czech Republic
The rising environmental concerns and shortage of fossil compounds present some great challenges for the polymer industry and the use of traditional synthetic polymers [1]. Among others, these concerns spurred the efforts like the European
Data Loading...
