Microstructural details and polymorphs in poly(propylene‐ co ‐1‐nonene) copolymers synthesized at different polymerization temperatures

Abstract

Several copolymers based on propylene with 1-nonene as comonomer have been synthesized within a wide range of compositions using a metallocene catalyst and different temperatures. The effect of the two main variables, comonomer content and polymerization temperature, on the final microstructure obtained (polymerization activity, stereochemistry and molar mass, among other details) as well as on the capability of crystallization, formation of distinct polymorphs and phase transitions, is examined. Different ordered entities are developed in these isotactic poly(propylene-co-1-nonene) copolymers depending on 1-nonene molar content: monoclinic, orthorhombic, and mesomorphic ones. A detailed analysis of the phase transitions involved is performed using real-time variable-temperature wide-angle diffraction experiments with synchrotron radiation on the sample with the highest comonomer amount. Different crystallization conditions were tested in order to attain information of the whole phase behavior. From these results, it was found that the mesophase of isotactic poly(propylene) is competing with the crystalline structures, although it recrystallizes on melting into the monoclinic phase at common differential scanning calorimetry rates.

Thermal behaviour and crystallization analysis of ethylene‐propylene (EP) copolymer and EP‐styrene terpolymer

“…The loss in T c and crystallinity is assigned to the formation of short‐chain branching during ter‐polymerization post‐styrene addition. [ 28 ] It is interesting to note that the addition of NiCr LDH as well as sonication treatment had an insignificant impact on the corresponding T m , T c , and crystallinity values.…”

Thermal Degradation Kinetics Analysis of Ethylene-Propylene Copolymer and EP-1-Hexene Terpolymer

“…The increase in activity is the attribute of the comonomer presence. The activity enhanced due to different factors, improved solubility of the macro chain in the medium offering high solubility of the monomer gases, higher chain transfer activity, and modification of active center quality [ 48 , 49 , 50 ]. A similar study was reported by Da Silva et al [ 50 ]., where, the terpolymer of ethylene-propylene-1-pentene showed a higher yield with respect to the homopolymer.…”

“…Increasing 1-Hexene concentration showed a gradual decrease in the crystallinity and the melting temperature of the polymer. These attributes of the terpolymer could be because of the presence of short-chain branching (SCB) or due to enhanced chain transfer activity leading to the formation of low molecular weight and short-chain-branched polymer [ 48 , 49 ].…”

Nanocomposites of PCL and SBA-15 Particles Prepared by Extrusion: Structural Characteristics, Confinement of PCL Chains within SBA-15 Nanometric Channels and Mechanical Behavior

“…Two different processes are considered to be present in this interval. The first one is the annealing of the initially imperfect crystals at room temperature [ 37 , 38 , 39 , 40 ]. The as-processed films were maintained for 2 days at ambient conditions before the DSC experiments, and during that time, the imperfect crystallites were able to thicken, thus increasing their melting temperature.…”