Cork–polymer biocomposites: Mechanical, structural and thermal properties

Abstract

a b s t r a c tThis work addresses to the preparation of biocomposites resulting from the combination of different biodegradable aliphatic polyesters with cork (30 wt.%). The lignocellulosic biomass with closed cellular structure was compounded with poly(L-lactic acid) (PLLA), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), poly-e-caprolactone (PCL) and starch-poly-e-caprolactone (SPCL) blend using a twin-screw extruder prior to injection moulding into tensile samples. The physico-mechanical and thermal properties of the matrices and the bio-based cork composites were investigated. This study shows that the addition of cork contributes to produce lightweight materials using PLLA and PHBV matrices and promotes an increase on the stiffness of PCL. The fracture morphology observations showed good physical cork-matrix bonding with absence of voids or cavities between cork and the bio-based polyesters. Cork increases the crystallinity degree of the biocomposites. These findings suggest that the cork-polymer biocomposites are a viable alternative to develop more sustainable composite materials, such as automotive interior parts and bio-based caps for wine bottles as it has been shown as proof-of-concept.

Cork biomass biocomposites

“…Polymers from renewable resources have attracted an increasing attention, predominantly due to two major reasons: firstly, environmental concerns and secondly, the fact that our petroleum resources are limited [60]. More recently, CPC materials were produced using bio-based polyester matrices such as synthetic polymers from natural monomers, named poly(lactic acid) (PLA) and poly(l-lactic acid) (PLLA); polymers from microbial fermentation, such as polyhydroxybutyrate-cohydroxyvalerate (PHBV); and biodegradable polyesters, such as poly(caprolactone) (PCL) and starch-poly(caprolactone) (SPCL), starch being a natural polymer starch [14,61,62]. In all cases, the biocomposites showed a good dispersion of cork biomass and a strong interfacial adhesion between the cork particles and the polymeric matrices.…”

“…In all cases, the biocomposites showed a good dispersion of cork biomass and a strong interfacial adhesion between the cork particles and the polymeric matrices. Moreover, combining melt mixing or extrusion followed by injection molding processes reduces significantly the composite density by the use of cork biomass [14,61]. Thus, by using this strategy, it was possible to obtain lightweight cork biocomposite materials.…”

“…Fig. 17.4 shows a possible application as biodegradable caps for wine bottles [61], obtained by two melt-based steps: extrusion to produce the bio-based cork composite pellets and injection molding, the last process being used for the formation of parts with excellent dimensional accuracy. In this work, it combined different biodegradable aliphatic polyesters (i.e., PLLA, PHBV, PCL, and SPCL) with cork at 30 wt%.…”

A natural and renewable biosorbent phase as a low‐cost approach in disposable pipette extraction technique for the determination of emerging contaminants in lake water samples

“…This molecule is a hydrophobic polymer and, with suberin, constitutes the main part of the composition of cork oak tree Quercus Suber L. Consisting of a natural and biodegradable material, cork is a sustainable tool for the development of environmentallyfriendly analytical methodologies. Cork possesses a number of applications due to the properties, such as an insulating material [6]. Cork powder has already been employed as highly efficient sorbent phase in the development of sample preparation methods involving SPME and bar adsorptive microextraction (BAμE) [7][8][9][10].…”

Simultaneously improving stiffness, toughness, and heat deflection resistance of polylactide using the strategy of orientation crystallization amplified by interfacial interactions

“…However, owing to the slow crystallization rate and semirigid molecular backbone of PLA, articles obtained by conventional processing with high crystallinity remain a great challenge. In melt‐processing technologies such as injection molding, high mold temperature and long molding cycle is usually required in order to obtain PLA parts with high crystallinity, but this will undoubtedly increase the cost of production and energy consumption . Besides, nucleating agent and thermal annealing can induce matrix crystallization .…”