Water absorption and hydrothermal performance of PHBV/sisal biocomposites

Abstract

The performance of biocompositesof polyhydroxybutyrate-co-valerate (PHBV) and sisal fibre subjected to hydrothermal tests at different temperatures above the glass transition of PHBV (TH= 26, 36 and 46 ºC) was evaluated in this study. The influences of both the fibre content and presence of coupling agent were focused. The water absorption capability and water diffusion rate were considered for a statistical factorial analysis. Afterwards, the physico-chemical properties of water-saturated biocomposites was assessed by Fourier-Transform Infrared Analysis, Size-Exclusion Chromatography, Differential Scanning Calorimetry and Scanning Electron Microscopy. It was found that the diffusion rate increased withboth temperature and percentage of fibre, whereas the amount of absorbed water was only influenced by fibre content. The use of coupling agent was only relevant at the initial stages of the hydrothermal test, giving an increase in the diffusion rate. Although the chemical structure and thermal properties of water-saturated biocomposites remained practically inherent to hydrolytical degradation, the physical performance was considerably affected, due to the swelling of fibres, which internally blow-up the PHBV matrix, provoking cracks and fibre detachment.

Relevant factors for the eco-design of polylactide/sisal biocomposites to control biodegradation in soil in an end-of-life scenario

“…This fact is in agreement with the results of Le Duigou et al for polylactide/flax biocomposites [43], where the reduction of molar mass was explained as a result of chain breakage in the polymer matrix during processing, which is hindered by the increase of viscosity and shear of the fibre during processing. Similar results were obtained during the preparation of poly(hydroxybutyrate-co-valerate)/sisal biocomposites [9] or polylactide reinforced with cellulose kraft pulp [44].…”

“…The use of sisal [5] has been reported for biopolymers such as polylactide [6]- [8], poly(hydroxyl butyrate-co-valerate) [9], [10], starch-based matrixes [11]- [13] or chitosan [14]. Natural fibres such as sisal present low densities, low cost, non-abrasive nature, high filling level, low energy consumption, high specific properties, biodegradability, etc., over synthetic fibres.…”

Effect of bamboo fibers with different coupling agents on the properties of poly(hydroxybutyrate‐co‐valerate) biocomposites

“…Some mechanical properties of PHBV are similar to those of a polyolefin, and its good biocompatibility and biodegradability render it widely useful in food packaging and biomedical fields; however, its narrow processing window, poor mechanical properties, and high costs have limited its application . Natural fibers have been used to reinforce related biopolymers because of their low cost and desirable properties, in addition to their good reproducibility and degradability . Numerous studies have thus far led to advances in fiber/polymer composites, which play a role in efficiently reinforcing both thermoplastic and thermosetting polymers .…”

Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites

“…These materials should be carefully managed when their service lives (Badia et al, 2014, Gil-Castell et al, 2014 are completed due to both exhaustion of performance or fast disposal of products with short-time uses, even with retained properties. Though bio-disposal facilities might be the logical step forward on waste management, the energetic options should be also considered (Al-Salem et al, 2009), taking into account that the accumulation of polymeric biowaste will potentially increase.…”