Nucleation Effects of a Novel Nucleating Agent Bicyclic [2,2,1] Heptane Di-carboxylate in Isotactic Polypropylene

Abstract

Nucleation effects of a novel nucleating agent, bicyclic [2,2,1] heptane di-carboxylate (commercial product name: , in isotactic polypropylene (iPP) were studied by using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The results showed that HPN-68 is a typical nucleating agent for α-iPP and has high nucleation efficiency. Crystallization peak temperature and mechanical properties of iPP nucleated with HPN-68 can be greatly increased with only a low concentration of HPN-68. However, increased concentration of HPN-68 has a saturation value and properties of iPP, which tend to plateau when the concentration of HPN-68 exceeds the saturation value. When the concentration of HPN-68 was 0.2 wt%, the crystallization peak temperature was increased by about 15 • C, and the tensile strength and flexural modulus of iPP were increased by 13% and 18%, respectively.

Properties and Crystallization Behaviors of Isotactic Polypropylene Under Action of an Effective Nucleating Agent

“…So far, to the best of our showed excellent nucleation efficiency in iPP at very low addition amount (e.g., 0.20wt%). When the addition amount of Hyperform HPN-20E in iPP was 0.20wt%, compared to those of pure iPP, the tensile strength, tensile modulus, flexural strength and flexural modulus were increased by 10.81%, 8.65%, 16.67% and 11.96%, respectively, which was comparable to the effect on mechanical properties of a highly effective commercial nucleating agent, Hyperform HPN-68 [30], indicating that Hyperform HPN-20E was highly effective for iPP. When the addition amount of Hyperform HPN-20E in iPP was low, it was difficult for the nucleating agent particles incorporated into the iPP to agglomerate together and all particles played the role of nuclei.…”

“…0.15wt%. When the amount of Hyperform HPN-20E in iPP was 0.2wt%, compared to that of pure iPP, the haze value of iPP was decreased by 42.44%, which was better than that of iPP nucleated with Hyperform HPN-68 [30]. The addition of the nucleating agent into iPP presumably reduced the spherulite size of iPP, resulting in improved transparency of iPP as the haze value was decreased greatly.…”

“…The increase was comparable to that of iPP nucleated with Hyperform HPN-68 (increased by ca. 15°C) [30]. According to the criterion proposed by Rybnikar [33,34] for evaluating the nucleation efficiency of a nucleating agent, the difference between the crystallization peak temperature both the crystal nucleation rate and the crystal growth rate.…”

Structure and properties of aβ-nucleated polypropylene impact copolymer

“…It has been comprehensively shown that the addition of nucleating agents can affect the crystallisation of a semi‐crystalline polymer like iPP. Structural polymorphism of iPP exists within its crystalline domain; among the crystalline polymorphs present, the β ‐crystalline phase has been shown to contribute to properties such as increased elongation at break, improved ductility and higher impact strength . The β ‐polymorph phase may be induced in iPP by the use of β ‐nucleating agents ( β ‐NAs), but will never inhibit the formation of the more commonly found phase ( α ‐polymorph) .…”

Effect of molecular architecture on the crystalline structure and stiffness of iPP homopolymers: Modeling based on annealing experiments

“…The properties of crystalline polymers are determined by their structure which can be modified by two main approaches: i) to control molecular structure and increase chain regularity 6,7 or ii) to use nucleating agents [8][9][10][11][12][13][14] . Modern polymerization and catalyst technology reached very high levels, further progress is difficult.…”