BASALT FIBER REINFORCED POLY(LACTIC ACID) COMPOSITES FOR ENGINEERING APPLICATIONS

摘要

Nowadays, due to the increasing environmental consciousness bio-based and biodegradable polymers (biopolymers in short) are located in the focus of interest. By replacing conventional, petrol based polymers with biopolymers the urging waste management problems could be moderated or even solved, moreover, the petrol-dependency of plastic industry could be decreased, and in the future a new, biomass-based (mainly starch and cellulose based) plastic industry could be launched. However, nowadays, the biopolymer production in the World is only around 0.5% of the overall plastic production, but it is believed to increase significantly in the upcoming decades. One of the most promising biopolymer is Poly(Lactic Acid) (PLA) [1-4], which can be produced by the fermentation of starch and sugar into lactic acid and the polycondensation of the lactic acid itself. Due to the fact that starch can be found all over the World in high amounts in agricultural plants like corn (maize), wheat, rice, potato, tapioca, it can be seen easily that PLA could be the first widely used pioneer of the biomass-based plastic industry. PLA is a thermoplastic material, thus it can be processed by using conventional thermoplastic processing equipments like injection molding, extrusion, thermoforming, compression or blow molding. It also has good mechanical properties, tensile strength of 60 MPa, tensile modulus of 3 GPa, however, it is considered as a brittle material with a Charpy notched and unnotched impact strength of 2.7 and 23.0 kJ/m~2 respectively, and also its low heat deflection temperature (HDT) of 50-60°C according to its low glass transition temperature (T_g) only allows it to be used in indoor applications. At the same time, its biodegradation only takes place in industrial compost (above 60°C) after an initial hydrolysis, thus the PLA products can be used for years at room-temperature, which makes PLA even an intelligent polymer. Nowadays, PLA products are already commercialized and more and more PLA products are on the market, however, these products are mainly related to the packaging industry.