The polymerization was performed under suitable conditions at isobutylene vaporization temperature (-7°C). Experiments revealed that polymerization induced by "H-Maghnite" proceed in bulk and in solution. In contrast to findings with methylene chloride CH 2 Cl 2 as a polar solvent, polymerization yields with hexane C 6 H 14 non-polar solvent is very significant.In bulk polymerization, Isobutylene conversion increases with increasing "H-Maghnite" proportion.
Although desirable for biomedical applications, soft degradable elastomers having balanced amphiphilic behaviour are rarely described in the literature. Indeed, mainly highly hydrophobic elastomers or very hydrophilic elastomers with hydrogel behaviours are found. In this work, we developed thermoset degradable elastomers based on the photo-cross-linking of poly(lactide)-poly(ethylene glycol)-poly(lactide) (PLA-PEG-PLA) triblock prepolymers. The originality of the proposed elastomers comes from the careful choice of the prepolymer amphiphilicity and from the possible modulation of their mechanical properties and degradation rates provided by cross-linkers of different nature. This is illustrated with the hydrophobic and rigid 2,4,6-triallyloxy-1,3,5-triazine compared to the hydrophilic and soft pentaerythritol triallyl ether. Thermal properties, mechanical properties, swelling behaviours, degradation rates and cytocompatibility have been evaluated. Results show that it is possible to generate a family of degradable elastomers covering a broad range of properties from a single biocompatible and biodegradable prepolymer.
A new green polymerization technique to synthesis polylimonene (PLM) is carried out in this work. This technique consists of using Maghnite-H + as eco-catalyst to replace Friedel-Crafts catalysts which are toxics. Maghnite-H + is a montmorillonite silicate sheet clay which is prepared through a simple exchange process. Polymerization experiments are performed in bulk and in solution using CH2Cl2 as solvent. Effect of reaction time, temperature and amount of catalyst is studied, in order to find the optimal reaction conditions. The polymerization in solution leads to the best yield (48.5%) at -5 °C for a reaction time of 6 h but the bulk polymerization, that is performed at 25 °C, remains preferred even if the yield is lower (40.3%) in order to respect the principles of a green chemistry which recommend syntheses under mild conditions, without solvents and at room temperature. The structure of the obtained polymer (PLM) is confirmed by FT-IR and Nuclear Magnetic Resonance of proton ( 1 H-NMR). The glass transition temperature (Tg) of the polylimonene is defined using Differential Scanning Calorimetry (DSC) and is between 113 °C and 116 °C. The molecular weight of the obtained polymer is determined by Gel Permeation Chromatography (GPC) analysis and is about 1360 g/mol.
Abstract-In the present work the ring-opening polymerization of ε-caprolactone using a protonexchanged montmorillonite clay as initiator is reported. The influences of reaction temperature, solvent, weight ratio of initiator/monomer and reaction time on the conversion of monomer and the molecular weight are investigated. The kinetics indicated that the polymerization rate is first order with respect to monomer concentration. Mechanism studies showed that monomer was inserted into the growing chains by acyl-oxygen bond scission rather than the break of alkyl-oxygen bond.
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