An investigation on the possible use of coffee silverskin in PLA/PBS composites

Abstract

The production of degradable packaging materials is a task that can be no longer postponed. Moreover, high amounts of agricultural wastes are landfilled without any recycling. In this research, the possibility to formulate particulate composites made of biopolymers filled with coffee waste with acceptable physical and mechanical characteristics that will degrade is investigated. The addition of this agricultural waste, by reducing the requested amount of biopolymer, can decrease the overall price of the material presently the main limiting factor to the use of biopolymers in the packaging industry. Silverskin, the integument of coffee beans discarded during the roasting process, after a milling step, is added up to a 30 wt% either to polylactic acid (PLA) or to a blend of PLA and polybutylene succinate. The filler can be homogeneously dispersed in both systems. The data shows that the silverskin filler increases the elastic modulus but decreases the tensile strength of the material and helps the development of crystal phase in the matrix. The thermal stability and the hydrophobicity of the materials stay almost unchanged on filler addition. Moreover, data shows that the addition of silverskin increases the materials susceptibility to microbial attack.

The biocomposites properties of compounded poly(lactic acid) with untreated and treated spent coffee grounds

“…Coffee is one of the world top three non‐alcoholic beverages (coffee, cocoa, and tea), which consumption leaps to the first. Massive quantities of bio‐wastes (SCG, 15 coffee silverskin, 16 coffee oil) from the manufacturing process has not been effectively treated and utilized. In the spirit of the theme mentioned above, a lot of literature on spent coffee grounds‐polymer composites have sprung up in recent years 17–21 …”

Crystallization behavior analysis and reducing thermal shrinkage of poly(lactic acid) miscibilized with poly(butylene succinate) film for food packaging

“…Previously, the formation of a crystalline PLA network through strain‐ or thermal‐induced crystallization and blending with highly crystalline molecules have been reported to restrict the free movement of amorphous PLA chains with a consequent enhancement of thermal dimensional stability 7,9 . Blending PLA with PBS is another promising approach due to the high impact strength, thermal resistance, and fully biodegradability of PBS 10–15 . Hassan et al found that the increases in PLA decomposition temperature and ductility were proportional to the PBS content in the PLA/PBS blends 10 .…”

“…7,9 Blending PLA with PBS is another promising approach due to the high impact strength, thermal resistance, and fully biodegradability of PBS. [10][11][12][13][14][15] Hassan et al found that the increases in PLA decomposition temperature and ductility were proportional to the PBS content in the PLA/PBS blends. 10 Additionally, PBS functioned as a plasticizer for PLA molecules by decreasing the T g of PLA and improved ductility of PLA/PBS blend.…”

Effect of fiber surface treatment on mechanical, interfacial, and moisture absorption properties of cattail fiber‐reinforced composites

“…Natural lignocellulosic fibers, such as flax, hemp, ramie, kenaf, sisal, and jute, have been studied as sustainable substitutes for glass fibers for reinforcing polymer matrix composites. [1][2][3][4][5][6][7][8][9][10][11][12] In terms of specific mechanical properties, these plant-based fibers, extracted from bast, leaves, seeds, fruits, wood, stalks, and grasses/reeds, [13][14][15] are on par with those of glass fibers. [16][17][18] The properties of the natural fiber composites are influenced by the properties of the fiber, fiber aspect ratio, fiber orientation, fiber moisture absorption, and fiber volume fraction.…”

“…Natural fibers are preferable as reinforcement for polymer matrix composites because of their low density and renewability over synthetic fibers. Natural lignocellulosic fibers, such as flax, hemp, ramie, kenaf, sisal, and jute, have been studied as sustainable substitutes for glass fibers for reinforcing polymer matrix composites 1–12 . In terms of specific mechanical properties, these plant‐based fibers, extracted from bast, leaves, seeds, fruits, wood, stalks, and grasses/reeds, 13–15 are on par with those of glass fibers 16–18 …”