Development of bio-based membranes for building envelope applications from poly(lactic acid) and cellulose microfibers

Abstract

A bio-based membrane was developed for building envelope applications. Biocomposites with enhanced water vapor permeability were fabricated based on poly(lactic acid) (PLA) and cellulose microfibers (CMF). To improve the interfacial adhesion between PLA and fibers, polyethylene glycol (PEG) was used as a compatibilizer for the modification of CMF. The properties of prepared PLA-based biocomposites were investigated in terms of their morphology, thermal stability, thermomechanical properties, and water vapor permeability. The morphological investigation showed the improved dispersion of cellulose fibers in the PLA matrix after modification of the bio-filler with PEG. The thermogravimetric analysis illustrated that the addition of modified CMFs increased the thermal stability of materials. Moreover, the water vapor permeability of PLA-based biocomposites was enhanced by adding modified CMFs to the PLA matrix. The results suggest that the utilization of PEG as a biopolymer compatibilizer represents a cost-effective and environmentally friendly method to improve the properties of PLA/CMF biocomposites. The developed membranes are potential materials for the fabrication of bio-based membranes with permeable properties that facilitate the transmission of entrapped water vapor through the building, eventually prolonging the service life of building envelope materials.

Vapor barrier membranes based on polylactic acid and cellulose microfibers for the building envelope application

“…A similar result was reported by Botta et al in PLA/graphene composites, where the thermal degradation temperatures of materials was shifted towards higher values in the presence of graphene nanoparticles [43]. It can be concluded that the addition of highly thermally stable CMF bio-ller into PLA protected polymer chains from the thermal decomposition, thereby improving the thermal stability of materials [31].…”

“…2a). The presence of aggregates is because of the van der Waals force and hydrogen bonding between hydroxyl groups of CMF [31]. Figure 2b indicates that the morphology of bers became more de ned and uniform after the modi cation of CMF with LA.…”

“…5b. The untreated CMF showed a decomposition temperature (T d ) of 340.1°C, which is attributed to the breakage of glycosidic bonds in cellulose [31]. After the modi cation, the value of T d enhanced to 345.3°C.…”

“…For instance, the storage modulus of PLAC composites incorporated with 5, 10, and 20 wt% of untreated CMF were 1163.5, 896.3, and 669.4 MPa, respectively. The results might be because of the agglomeration of untreated CMF in the PLA matrix that negatively affect the storage modulus of materials [31].…”

“…These di culties could be addressed by the surface modi cation of CMF to improve the compatibility and interfacial adhesion between bers and the polymer matrix [23]. Recently, numerous studies have investigated the modi cation effect of cellulose bers with esteri cation [24], oxidation/amidation [25], silanization [26], alkalization [27], sol-gel [28], surfactant [29], plasticizer [30], and polymer grafting [31], etc., and the obtained results indicated the improved dispersion of modi ed bers in the polymer matrix. For instance, Sethi et al reported a rapid and eco-friendly sustainable method for functionalization of cellulose nano bers (CNFs) with lactic acid (LA).…”