Nonisothermal crystallization behaviors of ethylene–acrylic acid copolymer and ethylene–acrylic acid copolymer/chloroprene rubber thermoplastic vulcanizate

Abstract

<jats:p> Nonisothermal crystallization kinetics of ethylene–acrylic acid copolymer (EAA) and thermoplastic vulcanizate (TPV) based on EAA/chloroprene rubber (CR) were extensively studied using differential scanning calorimetry. Several methods, including the Avrami, Ozawa, and Mo equations, were carried out to analyze the process of nonisothermal crystallization kinetics of EAA and EAA/CR TPV. The results showed that the Avrami analysis modified by Jeziorny and a method developed by Mo could describe the nonisothermal crystallizations of pure EAA and the EAA/CR TPV very well. However, the Ozawa analysis did not give an adequate description. The crystallization processes of pure EAA and the EAA/CR TPV were accelerated by increasing the cooling rates. Moreover, the initial crystallization temperature and the crystallization termination temperature of EAA/CR TPV were higher than those of pure EAA at the same cooling rate, thus showing the nucleating function of CR in the beginning. While the crystallization half time of EAA/CR TPV was apparently longer than that of pure EAA, meaning that the more CR could cause the steric effect and retard the crystallization process of the TPV during the late stages of crystallizing. Although the CR phase of EAA/CR TPV could provide more nucleation sites, the presence of more CR phase must impose a much more significant confinement effect on the crystal growth of EAA. It was believed that this confinement effect overweighed the nucleation effect, thereby slowing down the overall crystallization rate. </jats:p>

Nonisothermal crystallization kinetic behavior of pure ethylene-Vinyl acetate copolymers and ethylene-Vinyl acetate copolymer/nitrile rubber thermoplastic vulcanizate

“…In this research, both the Jeziorny method and the Mo method were successful in describing the nonisothermal crystallization behavior of the EVA/NBR TPV, while the Ozawa method failed to describe the nonisothermal crystallization behavior. This result is similar to the findings of our previous research, 28,37 the research further proved the identical perspective.…”

“…This phenomenon can be explained by the fact that with increasing cooling rate, the rate of molecular chain exclusion into the crystal lattice cannot match the cooling rate, resulting in restricted crystallization. 28 The nonisothermal crystallization process can be described by an equation that expresses the relationship between crystallization temperature (T) and crystallization time (t) in the following manner Where T denotes the temperature at t, T o represents the initial temperature of crystallization and φ represents the constant cooling rate. Figure 3 displays the relative crystallinity versus crystallization time curves for pure EVA and EVA/NBR TPV at various cooling rates.…”

“…This phenomenon can be explained by the fact that with increasing cooling rate, the rate of molecular chain exclusion into the crystal lattice cannot match the cooling rate, resulting in restricted crystallization. 28

Figure 2.Development of relative crystallinity versus temperature during nonisothermal crystallization at four cooling rates. (a) pure EVA; (b) EVA/NBR TPV (weigh ratio = 70/30).

…”

Crystallization and fusion kinetics of Poly(butylene terephthalate)/Titanium Dioxide

“…F increased with the degree of crystallization, i.e., for higher crystallinity much energy must be supplied to the system; a quite similar trend was observed for PP/PET blends as reported by Zhu et al [49] . Related to TiO 2 addition, PBT composites displayed higher F suggesting that with the crystallization development the composites need much energy [50][51][52] .…”

Modification on PBS using epoxy-functionalized core-shell starch particles

“…In recent years, core-shell impact modi ers such as acrylate rubber (ACR) [8][9][10] , acrylonitrile-butadienestyrene copolymer (ABS) [11] , and methyl methacrylate-butadiene-styrene copolymer(MBS) [12,13] have gained widespread attention from researchers as e cient toughening agents. Yang et al [10] .…”