Hydrogenated butadiene/ethene/1‐olefin terpolymers as model substances for short‐chain branched polyethylene

Abstract

Poly [(butadiene-ah-ethene)-co-(butadiene-alf-1-olefin)] terpolymers were synthesized by Ziegler-Natta polymerization using VO(O-ne~pentyl),CVAl(i-Bu)~ catalyst system in toluene. Variation of the 1-olefidethene ratio in the monomer feed produces terpolymers with mixed units of butadiene-alt-ethene and butadiene-alt-1 -olefin. After hydrogenation one obtains model substances for LLDPE with a special distribution of methylene sequences between branching points. Differential scanning calorimetry (DSC) was used to determine the degree of crystallinity and the melting behavior. From the melting temperature region, the thickness distribution of the crystal lamellae, and thus the average number of C-atoms between the alkyl branches, can be determined. From detailed X-ray diffractometry, the mean crystallite size, the lattice distortions and the degree of crystallinity was determined for those products which show distinct reflections. The crystallization behavior can only be described by a three-phase model.

gem‐Dimethyl Effects in the Thermal Behavior of Polyethylene

“…These ADMET polymers were made using symmetric a,o-diene monomers followed by hydrogenation of the unsaturated polymer (see Scheme 1). [17][18][19][20] Consistent with the methyl branch study mentioned above, these model functionalized polyethylenes (3)(4)(5)(6)(7)(8) also exhibit sharper, more defined melting endotherms and melting points that are lower than their random, chain-made counterparts. Further, an analogous series of ethylene-based model copolymers was prepared possessing perfectly spaced, functional group branches on every 19 th carbon atom.…”

“…Other studies focused on the preparation of model polymers of polyethylene with regularly placed comonomers such as carbon monoxide (3), vinyl acetate (4a-d), methyl acrylate (5a-b), ethyl acrylate (6), styrene (7), and vinyl chloride (8). These ADMET polymers were made using symmetric a,o-diene monomers followed by hydrogenation of the unsaturated polymer (see Scheme 1).…”

“…Its broad applicability results from being able to alter crystallinity within the polymer, a structural feature dictated by random branching along the polymer backbone 1. Consequently, branching in polyethylene has been a subject of extensive study for more than 60 years now,2–7 where the goal has been and remains today to properly elucidate structure‐property relationships for this polymer. Branches in polyethylene result either from chain transfer during the chain propagation, or as a consequence of purposeful introduction of them via Ziegler‐Natta8,9 or metallocene10,11 chain copolymerization chemistry.…”

Separation of components of different molecular mobility by calorimetry, dynamic mechanical and dielectric spectroscopy

“…The heat of fusion of about 12 kJ tool -' shows that only a small part of the molecule, may be parts of the alkane chains, are involved in this crystallization. The observed melting temperature of 246 K corresponds to a crystallized alkane chain of about 10 carbon atoms [35,36]. We will investigate this in more detail in the future.…”

A Study on the Coordination Polymerization Using C2-Symmetric Dichloro[rac-ethylenebisindenyl] zirconium(IV)/Methylaluminoxane System

“…[7][8][9] The main reason for carrying out research on the terpolymers is to examine the influence of termonomers on the properties of EPDM-rubbers and block-terpolymers. 10,11 In particular, studies on the terpolymers with reactive groups has been limited even though it maybe possible to use the terpolymers to develop new high-functional polyolefins. [12][13][14][15] In this study, we prepared a polyethylene (PE), poly(ethylene-co-1-decene) (PED), and poly(ethylene-co-p-methylstyrene) (PEM), and poly(ethylene-ter-1-decene-ter-p-methylstyrene) (PEDM) using a bridged metallocene catalyst and a cocatalyst system.…”