Studies on the degradable polyethylenes: Use of coated photodegradants with biopolymers

Abstract

SYNOPSISThree degradable polymer materials such as starch-polyethylene (PE) binary blends, P E containing starch and a photoactivator, and PE containing starch and a photoactivator which was coated with gelatin were prepared and their degrees of photodegradation and/ or photodegradation after biodegradation were investigated. The addition of the gelatincoated ferric salt in PE extended the induction period of degradation and accelerated photodegradation after the removal of coating material by biodegradation. This result suggested that the degradation rate of P E could be controlled if more powerful photoactivators and/ or coating material are developed and their contents are optimized. 0 1996

A New Method to Synthesize Microcapsule and Its Application in Controllable Photodegradation of Polymers

“…The coated fraction of particles can be calculated from this relationship since the absorptivity at t = 0 is related to the uncoated or partially coated particles. In this way, we found that the coated fraction of microcapsules is about 91.6% and that the value decreases to 80.4% after hydrolyzed in 1 M HCl solution at 40 • C for 3 h. Compared with the degree of coating (60%) in literature, 7 the coated fraction in our experiments is much higher.…”

“…Carbonyl index (CI) is a convenient indication of degradation degree. 7,15 Figure 4 demonstrates the increasing of CI with photodegradation time. There is not significant difference between the films containing unhydrolyzed and partly hydrolyzed microcapsules of photodegradant at the first 4 days.…”

“…[1][2][3][4][5][6] It is a recently developed concept that microencapsulated photodegradant was used in the controllable photodegradation of polymers 7 although microencapsulated antioxidants were adopted in polymers. 8 Usually the addition of photodegradant is accompanied with photostabilizers or antioxidants to overcome the problem of property decay of polymers during application.…”

A comparative study of different crosslinking agent-modified chitosan/corn cob biocomposite films

“…The CS/CC biocomposite specimens with dimension of 2 9 3 cm were taken out every 2 days and rinsed with distilled water to remove the excess of a-amylase enzyme on the surface of specimens. Then, the specimens were transferred to an oven at 50°C for 24 h. This method was noted by Yoon et al [19]. The weight loss of enzymatic degradation can be evaluated by using Eq.…”

A study of the degradation of compatibilized and uncompatibilized peanut shell powder/recycled polypropylene composites due to natural weathering

“…Natural fibers or fillers are used as reinforcing agents in polymer composites. Because natural fillers are biodegradable, the composites of natural fillers and polymers may offer a new class of materials that can provide environmental protection . The shells of peanuts, a food crop, generate a large amount of waste.…”