Photodegradation Mechanisms on Poly(ε-caprolactone) (PCL)

Abstract

Photodegradation of PCL was performed exposing injected specimens to ultraviolet radiation (UV-B) up to 9 weeks. Photodegradated PCL specimens were tested by Differential Scanning Calorimetry (DSC), Infrared Spectroscopy (FTIR), mechanical properties, Optical Microscopy (MO) and Scanning Electron Microscopy (SEM).Upon exposure decrease in elongation at break and increase of elastic modulus were verified, higher degree of crystallinity was observed for longer exposure what can be due to the chemi-crystallization mechanism. From IR spectra new carbonyl group (C=O) peaks were observed. Presence of micro cracks on specimens' surface was identified by MO. From morphological analyses is suggested that the photodegradation in PCL takes place by bulk erosion mechanism.

Photodegradation of polystyrene/rubber waste blends compatibilized with SBS copolymer

“…41,42 Figure 4 shows the elongation at break of HIPS and blends versus the exposure time. The literature [43][44][45][46] shows that it is the most sensitive mechanical property when it comes to the effects of photodegradation. The elongation at break in HIPS shows a drastic reduction for up to 45 days of exposure to photooxidation.…”

“…During the 60 days of exposure, it is observed that HIPS and blends have a recovery of the elongation at break, a fact that has already been observed in the literature. [41][42][43][44][45] This behavior can be attributed to a greater surface deterioration of the sample when the heavily degraded layer is pulled out from the sample and fails to transfer the applied stress to the subsequent layers. Consequently, only the inner layers are analyzed and, because they are less affected by UV radiation, the elongation at break values tend to increase.…”

“…As the aging time increases, the color of the samples does not change much, eventually maintaining a constant dark yellow color. According to the literature, 12,44 the yellowing is a clear indication of degradation with oxidation reactions, possibly due to chemical and physical changes from light absorption by the chromophore groups (intrinsic or extrinsic) as well as the formation of free radicals, which implies reductions in mechanical properties. The surface behavior of HIPS and the blends corroborates the FTIR analysis.…”

Biodegradable Compounds of Poly (Ɛ-Caprolactone)/Montmorillonite Clays

“…3,4 In this work poly (ɛ-caprolactone) (PCL) compounds were investigated; PCL is a linear, biodegradable and biocompatible aliphatic polyester commonly used in pharmaceuticals and dressings for wounds. 5,6 PCL is synthesized through ε-caprolactone ring-opening polymerization or by free-radical polymerization of 2-methylene-1,3-dioxepane. [7][8][9] Biodegradable polymers can be used in blends, composites and nanocomposites.…”

Properties and Morphology of Polypropylene/Big Bags Compounds

“…Currently due to the quick increase in the use of polymeric products, the Statista in 2016 shows the worldwide polypropylene (PP) production was 73.8 million tons, producing a large amount of post-consumer waste, and according to Sustainable Businesses only a small proportion of this plastic waste is recycled or reused, while a large amount of it is disposed in landfills causing serious environmental damage 1,2 . This serious scenario has worried the society and specifically the scientific community who has researched solutions for reusing and recycling these materials once they result in great problems mainly when improperly discarded in the environment and consequently, become a harmful material to the ecological system 3,4 . Consequently, there is an urgent requirement to develop "new products" made from residues i.e., with the insertion of post-consumer resins, in order to minimize the use of the virgin polymer, reducing costs and the disposal of materials [5][6][7][8][9] .…”