Compostable, fully biobased foams using PLA and micro cellulose for zero energy buildings

Abstract

Ecological, health and environmental concerns are driving the need for bio-resourced foams for the building industry. In this paper, we examine foams made from polylactic acid (PLA) and micro cellulose fibrils (MCF). To ensure no volatile organic compounds in the foam, supercritical CO2 (sc-CO2) physical foaming of melt mixed systems was conducted. Mechanical and thermal conductivity properties were determined and applied to a net zero energy model house. The results showed that MCF had a concentration dependent impact on the foams. First structurally, the presence of MCF led to an initial increase followed by a decrease of open porosity, higher bulk density, lower expansion ratios and cell size. Differential Scanning Calorimetry and Scanning Electron Microscopy revealed that MCF decreased the glass transition of PLA allowing for a decrease in cell wall thickness when MCF was added. The mechanical performance initially increased with MCF and then decreased. This trend was mimicked by thermal insulation which initially improved. Biodegradation tests showed that the presence of cellulose in PLA improved the compostability of the foams. A maximum comparative mineralization of 95% was obtained for the PLA foam with 3 wt.% MCF when expressed as a fractional percentage of the pure cellulose reference. Energy simulations run on a model house showed that relative to an insulation of polyurethane, the bio-resourced foams led to no more than a 12% increase in heating and cooling. The energy efficiency of the foams was best at low MCF fractions.

Expanding Poly(lactic acid) (PLA) and Polyhydroxyalkanoates (PHAs) Applications: A Review on Modifications and Effects

“…Figure 12 , Figure 13 and Figure 14 , show the concept of foam injection molding, foam extrusion and bead foaming, respectively. Such foams exhibit thermal and mechanical properties comparable to those of the currently used petroleum-based foams [ 23 , 280 ]. An improvement of the morphology of the foam cell via modification of polymer melt viscosity is believed to be feasible through the addition of lignocellulosic fibers.…”

Effect of Cellulose and Cellulose Nanocrystal Contents on the Biodegradation, under Composting Conditions, of Hierarchical PLA Biocomposites

“…The biodegradability of PLA [28][29][30][31][32] and its composites containing microsized cellulose [33][34][35][36][37] or nanocellulose [38][39][40][41][42] are well documented. These studies have shown that PLA is capable of biodegradation under both aerobic and anaerobic conditions and that it is more recalcitrant to biodegradation than polycaprolactone (PCL) and polyhydroxybutyrate (PHB).…”

Design and Control of Compostability in Synthetic Biopolyesters

“…61 Under controlled composting conditions at 58 °C (ISO 14855-2), PBS degrades slower with a longer incubation time compared to PεCL. 62 The intermediate 81 PLA + 3% microcellulose fibrils, 82 PLA + 5% clay, 83 PεCL at 25 °C, 84 PLA/PεCL/Thermoplastic starch (TPS) 60/10/30, 85 PεCL/HC 90/10, 86 PBAT/ PLA 60/40, 87 PBSA, 88 PBS, 89 PLA/TPS 50/50 and PBAT/TPS 43/57, 90 PBAT + 3% clay, 91 PHB/PεCL 75/25, 92 PHB, PHBV20, PHBV40, 93 PHB/cellulose 55/45, 94 cellulose, 82 PHBV + 3% clay, 91 PLA/TPS 60/40, 85 PBAT/TPS 60/40, 95 TPS, 96 rice starch, 97 PLA, and PLA/PHB 75/25 at 25 °C, 98 PεCL, 99 PεCL/cellulose acetate 80/20, 99 PεCL + 5% grape seed extract, 100 and PBS, PBS + 10% jute fibers. products in PBS degradation are 1,4-butanediol and succinic acid, which are readily metabolized by microorganisms through the citric acid cycle.…”