Physical Properties of the Poly(1-olefin)s. Thermal Behavior and Dilute Solution Properties.

Abstract

Poly(l-olefin)s from poly(l-butene) up to poly(1-octadecene) have been characterized. The melting point was measured by Differential Scanning Calorimetry (DSC-1B) and dilatometry, the specific volume and volume expansion coefficient by dilatometry, and the unperturbed chain dimension by intrinsic viscosity at near theta conditions. A trend is confirmed for melting points and revealed for expansion coefficients of first a decrease with increasing side-chain length in the polyolefins, followed by an increase with further increase in length. The minimum is near poly(1-hexene) and poly(1-heptene). The specific volume of the polytl-olefin) series exhibits a maximum around this same composition. The minima in melting point and thermal expansion coefficient and the maximum in specific volume are discussed in terms of chain-to-chain packing density. It is suggested that packing density is a minimum in this region. Two melting points were found for each of several higher poly(lolefin)s from poly(1-tridecene) up to poly(l-octadecene). It is found that the theta temperatures of the poly(l-olefin) series, as measured in two solvents, anisole and cyclohexanone, exhibit a minimum at poly(l-pentene). However, the characteristic ratios and the steric factors increase with increasing side-chain length for the entire series of measured poly(1olefin)s.

Higher ?-olefin polymerizations catalyzed byrac-Me2Si(1-C5H2-2-CH3-4-tBu)2Zr(NMe2)2/Al(iBu)3/[Ph3C][B(C6F5)4]

“…The small Δ H f values of poly(1‐hexene) and poly(1‐octene) propose the crystallizing limitation for long lateral POs. This may be one of the reasons why poly(1‐hexene) and poly(1‐octene) were reported mostly without melting point 1…”

“…In general, all higher α‐olefins can be polymerized by the various classes of Ziegler–Natta catalysts to mainly isotactic polymer 1–4. The polymerization rate decreases with increasing steric requirements, that is, both mere chain length in straight‐chain olefins leads to decrease, as does branching near to the double bond.…”

Polymerization of higher linear ?-olefins with (CH3)2Si(2-methylbenz[e]indenyl)2ZrCl2

“…2,5,14 X-ray diffraction analysis revealed that side-chain crystallinity predominates with an increasing num- ber of methylene groups for the higher homologues of the poly-␣-olefins. Wang et al 14 showed that side-chain crystallization occurs at least from poly-1-tridecene. In contrast to poly-1-pentene, the first heating cycle did not destroy the crystal structure of the higher poly-␣olefins prepared with 1, and the melting points of poly-1-decene, poly-1-tetradecene, and poly-1-octadecene could still be observed during the second heating cycle.…”

Catalytic Polymerization of Liquid Propylene: Effect of Low‐Yield Hexene Prepolymerization on Kinetics and Morphology

“…It is well known that, various classes of Ziegler-Natta catalysts can polymerize all higher alpha olefins, and mostly isotactic polymers are formed. [3][4][5][6] It is known that the type of prepolymer produced has a strong influence on the growth mechanism of the catalyst particle, but the extremely low-yield prepolymerization of higher alpha olefins and its influence on the final polymer morphology in a second liquid propylene polymerization has never been studied in open literature.…”