New PP/PLA/cellulose composites: effect of cellulose functionalization on accelerated weathering behavior (accelerated weathering behavior of new PP/PLA/cellulose composites)

Abstract

a Polylactic acid (PLA) was used as partial replacement for conventional thermoplastic matrix, new composites comprising cellulose, polypropylene (PP), and PLA being realized. In order to obtain a compatible interface between cellulosic pulp and polymeric matrix, two chemical modifications of cellulose with stearoyl chloride and toluene di-isocyanate (TDI) were performed, structural changes being evidenced by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The composite materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic scanning calorimetry, impact, tensile and melt rheological tests, surface tension, and dynamic vapor sorption. Because promising results for impact strength and Young modulus were recorded when replacing 15% of PP with PLA in blends of PP with the same cellulosic pulp load, the aim of our study was to assess the behavior to accelerate weathering of composites comprising PP, cellulosic pulp, and PLA. Although the slight decrease in the mechanical properties was recorded after accelerated weathering, the use of functionalized cellulose successfully prevented the deterioration of surface materials, especially for composite comprising stearoyl chloride treated cellulose pulp.

Development of masterbatch for composites using bamboo charcoal powders in poly(lactic) acid

“…[27] The oscillatory shear rheological properties of neat PLA and BC/PLA composites for shear storage modulus (G'), shear loss modulus (G 00 ), Han plots: storage modulus vs loss modulus, tan delta and viscosity, before and after weathering under severe condition: UV irradiation, moisture and high temperature for 300 and 600 hours were compared to nonaged samples as shown in Figures 1 to 5, respectively. PLA is a biodegradable polymer which is senstive to UV irradiation, moisture, and high temperature which is the same severe conditions experienced in weathering chamber; moreover, the polymer chain scission also gets induced by weathering [28] which is in concordance to the work conducted by Darie et al [29] and Spiridon et al [26] However, the addition of antioxidant improved the rheological properties of the aged samples as compared to those of aged neat PLA since the antioxidant can be able to prevent thermal oxidation reactions when the samples were exposed under conditions of high temperatures, and UV irradiation.…”

A Review of the Surface Modification of Cellulose and Nanocellulose Using Aliphatic and Aromatic Mono- and Di-Isocyanates

“…A PP/PLA composite was reinforced by birch pulp fibers after modifying the fibers with 2,4-TDI. The modification improved the mechanical and thermal properties, water resistance of the composite, and its stability upon weathering [83]. In the case of cellulose/PE composites, cellulose was modified using poly(methylene(polyphenyl isocyanate)), HMDI, and OI before compounding [69,84,85,86].…”

Preparation and Evaluation of Nanofibrous Hydroxypropyl Cellulose and β-Cyclodextrin Polyurethane Composite Mats

“…This technique was used to determine the equilibrium curves and diffusion coefficients of the prepared samples, based on second Fick's equation and the methods developed by Crank [52] and Balik [53]. As in a previous study [54], the diffusion coefficient (D) was calculated from the plot of normalized mass changing vs. time 1 2 . The graphs are illustrated in Figure 8, for both short and long times.…”