Polylactide/Biopolyethylene bioblends
In this work, Polylactide/Biopolyethylene blends were developed. Although some studies have been carried out on polylactide/polyethylene blends, none of them has used polyethylene synthesized with raw material obtained from natural sources. Due to the incompatibility between polylactide and polyethylene, E-GMA and EMA-GMA compatibilizers were used. These compatibilizers present glycidyl methacrylate groups in their structure, which may react with the functional end-groups of polylactide. To evaluate the properties, the blends were characterized by mechanical tests, scanning electron microscopy (SEM) and melt flow index (MFI). The results indicated that the compatibilizers played an important role in the blends, interacting with the blends components, modifying the morphology and improving the mechanical properties.
15 – Thermal Degradation
Thermal degradation begins to be important when polymers are processed and fabricated for use. The threshold temperature for breakdown determines the upper limit of temperature in fabrication and the volatile products of degradation must be known in order to guarantee the safety of workers. These same properties are relevant to the potential use of a polymeric material and, in the extreme case, to the hazards presented by the polymer in a fire situation. However, there are also some useful aspects of thermal degradation. Examination of the breakdown products from polymers is increasingly used as a method of analysis. In a limited number of cases, controlled thermal degradation is important in recycling of plastics waste and in the special case of carbon fibre production, degradative reactions are an essential part of the manufacturing process.
Thermal degradation of chlorinated rubber: Evidence for an alternative cyclic structure for chlorinated rubber
The thermal degradation under vacuum or in nitrogen of commercial chlorinated rubber (ICI Alloprene, 64.5 wt.-% chlorine) was studied by isothermal thermogravimetry and by simultaneous TG/TVA with programmed heating by using a Cahn RG thermobalance built into a thermal volatilization analysis (TVA) system. Analysis of volatile products was performed by titration and by spectroscopic methods. The only major degradation product is hydrogen chloride; five-sevenths of the total available hydrogen chloride is lost with great ease, and complete dehydrochlorination is very much easier than in poly(vinylidene chloride). Conjugation develops early in the degradation, but the minor products methane, ethylene, and hydrogen are observed in the later stages of reaction. These features cannot be reconciled with the previously proposed cyclic structure for chlorinated rubber, and an alternative structure which accounts well for the degradation behavior is suggested.