Biodegradable composite films based on waste gelatin

Abstract

SUMMARY: Gelatin, a naturally occurring polymer, is currently used in various applications comprising manufacturing of pharmaceutical products, x-ray and photographic films development and food processing. However, gelatin scraps generated in the different manufacturing processes may constitute a concern for the environment. Basically speaking, waste disposal deriving from plastics based on synthetic as well as semisynthetic polymeric materials, is becoming an increasingly difficult problem for their unfavorable volume-to-weight ratio and extremely wide variability of type, shape and composition of post consume plastic items that hinder the way to a general unique option for a simple and economically feasible management. As a partial solution to the global issue of plastic waste, in recent years much interest has been devoted to the formulation of environmentally degradable plastic items. Biodegradable mulching films were formulated from blends and composites based on waste gelatin and other natural waste such as sugarcane bagasse or synthetic materials such as PVA. Also, crosslinked films were produced using external or inherent crosslinker. The films were produced either by casting method or spraying on soil surface. The composites were submitted to biodegradation trials. The results showed that the films were biodegradable and the crosslinking could delay and predeterminate their biodegradation rate and extent.

Environmentally Degradable Bio‐Based Polymeric Blends and Composites

“…This behavior of gelatin can be attributed to the disruption of the helical structure of native gelatin allowing the chains to assume a random coil conformation with glutaraldehyde acting as a crosslinker among the chains 30. On the other hand, WGP80X and WGSCB20X did not show any significant difference in comparison with WGP80 and WGSCB20, thus indicating that 0.25% of glutaraldehyde has a negligible effect on blend properties, also in accordance with results from previous studies of water sensitivity and mineralization rates 26,31…”

“…Glutaraldehyde was used as crosslinking agent to improve water resistance and regulate degradation rate in soil of the hybrid films (Table 4). 26…”

Polyethylene‐collagen hydrolizate thermoplastic blends: Thermal and mechanical properties

“…Among biobased polymers, proteins have shown to be versatile materials that combine many valuable characteristics for technical applications such as good processability in the melt, excellent processability in solution, with good film and fiber forming capability. Thus protein‐based materials have been successfully blended with synthetic and natural polymeric matrices 4–9. The fairly high cost of protein and proteinaceous feedstocks when compared with some other biobased polymers, especially starch and cellulose, have somehow refrained research activity on their technical applications 10, 11…”

Preparation and characterization of biodegradable thermoplastic films based on collagen hydrolyzate

“…One of the ways to reach this goal is by using renewable, natural, low cost, and easily available biopolymers such as starch, 5,6 cellulose, 7 protein (collagen). [8][9][10][11] The majority of thermoplastics currently used as packaging materials are based on polyolefins, such as high density polyethylene (HDPE), low density polyethylene (LDPE), and polypropylene (PP). Moreover, for low value items such as shopping bags, agriculture mulch films, and food packaging (foils and thermoformed items) recycling would be neither practical nor economical.…”