Effect of Compatibilization on Poly-ε-Caprolactone Grafting onto Poly(ethylene-co-vinyl alcohol)

Abstract

Abstract:The non-miscibility of the reactants during solvent free poly-ε-caprolactone grafting onto poly(ethylene-co-vinyl alcohol) (EVOH) dramatically affects reaction kinetics. Different solutions were proposed to accelerate the exchange reactions between poly(ethylene-co-vinyl alcohol) and poly-ε-caprolactone. Reactions were conducted in a batch reactor or a mini twin-screw extruder. The addition of a poly(ethylene-co-vinyl alcohol)-g-poly-ε-caprolactone copolymer increased the compatibility of the reactants and led to a higher reaction rate. This copolymer was either prepared separately and added at the reaction beginning or prepared in situ grafting caprolactone from EVOH. The reactive system evolution was analyzed using molar mass evolution, microstructure characterization, thermal properties and the reactive blend morphology. The compatibilization effect combined with optimized reaction conditions, such as concentration and nature of catalyst and temperature, resulted in an important increase in reaction rates. Among the tested catalysts, 1,5,7-Triazabicyclo [4.4.0]dec-5-ene was a more efficient catalyst for grafting reactions than Tin (II) 2-ethylhexanoate.

Synthesis of Propylene-co-Styrenic Monomer Copolymers via Arylation of Chlorinated PP and Their Compatibilization for PP/PS Blend

“…As shown in Figure 1, the chain structure of chlorinated polypropylene is well characterized [12], but fairly complicated, consisting of chain units with isolated chlorine atoms (83.4%) including those at the tertiary (65.9%) and secondary (17.5%) carbon, neighboring chlorine atoms (6.4%), and small amounts of chlorine methane (10.1%). During the Friedel–Crafts alkylation reaction, the chlorine at different carbons causes the formation of different carbocation and gives rise to different chain units incorporated in the PP chain of the resulting copolymer when further reacted with substituted benzene [13,14]. Since the Friedel–Crafts alkylation reaction undergoes a carbocation mechanism, the carbocation intermediate also causes alternative C–C bond cleavage besides reacting with the substituted benzene, resulting in a decrease in the molecular weight of the copolymer.…”

Effects of antimicrobial agents on the thermal and mechanical properties of acrylate hydrogel matrices

“…As this study focuses on thin acrylate films, it can be considered that the effects are even more pronounced after a thermal solicitation of 200 °C. In addition, exchange reactions between small molecules formed during thermal reduction and acrylate matrix are probable causes …”

Improved thermostability and interfacial matching of nanoclay filler and ethylene vinyl alcohol matrix by silane‐modification

“…[14][15][16][17] On the other hand, surface modification of polymers is often accomplished by the grafting of polymers using common polymerization reactions. [18][19][20] Silanization of either the polymer or the nanoclay filler has also been described in the literature for this purpose. [21][22][23][24] However, to the best of our knowledge, the simultaneous use of silane coupling agents for the surface treatment of both polymers and nanoclays have so far not yet been described in the literature.…”

“…25 Surface energies are typically deter-mined via contact angle measurements or inverse gas chromatography (IGC). Although there are numerous reports dealing with the interfacial properties of either matrix systems or fillers intended for blending, 3,9,13,18,[26][27][28] no combined studies exist that focus on the quantitative characterization of the interfacial properties of ethylene vinyl alcohol and nanoclays where the interfacial properties of both components are modified in order to improve and adjust the intermolecular interaction forces.…”

“…Compatibilization of nanoclay is generally achieved by surfactant treatment, where an ionic bonding of organic surfactants to the silicate surface is established . On the other hand, surface modification of polymers is often accomplished by the grafting of polymers using common polymerization reactions . Silanization of either the polymer or the nanoclay filler has also been described in the literature for this purpose .…”