Polymethylene copolymer

Baker, C. H., and L. Mandelkern The crystallization and melting of copolymers. I — The effect of the crystallization temperature upon the apparent melting temperature of polymethylene copolymers. Polymer 7, 7 (1965). 

Cobalt extrudates were made according to the patent literature (12) by ex-ttuding a mixture containing a 50 wt.%Co / 50 wt.%Al alloy and polymethylene copolymers at 190°C and a throughput of 10 kg/h with a double wave extruder. To decon5)ose the polymethylene copolomers the extruded forms were then heated in an oven to 120°C followed by continual heating to 280°C within 90 minutes. Afterwards the temperature was ran d up to 800°C over 125 minutes and kept at this tenqserature for 140 minutes. The extrudates were then cooled, activated in a 20% caustic solution at 80°C over 120 minutes, washed, and stored under a mildly caustic aqueous solution (pH 10.5) imtil use. 

Fig. 5.2 Melting curves for polymethylene copolymers containing the indicated substituents as co-ingredients. Composition of copolymers is indicated as percentage of coingredient present. (From Richardson, Flory, and Jackson (20))...

We prepared polymers containing the mesogenic structure 25 of Table 1, both in the homopolymer form and as copolymers containing polysiloxane and decamethylene flexible spacers, and these polymers were compared in their properties to the earlier polymers prepared with a polymethylene spacer only The polymer with mesogenic structure 32 and the siloxane spacer showed a low molar enthalpy for the melt transition, while the copolymer and the polymer with the polymethylene spacer showed quite high melt enthalpies. 

The range of mesophase stability and melting temperature was greater for the polymer with a polymethylene spacer than that with a siloxane spacer however, the size of the entropy of clearing was reversed. In all such measurements, the properties of the copolymer fell between these two extremes, except for the case of the range of mesophase stability, which was greater for the copolymer than the two homopolymers. In all cases, the mesophases were identified as nematic from characterization by polari-zed-light microscopy. 

The polymer produced in eq 1.1 is known as polyethylene and, less commonly, as polymethylene, polyethene or polythene. (In the late 1960s, "polythene" became part of popular culture when the Beatles released "Polythene Pam.") Polyethylene is the lUPAC recommended name for homopolymer. As we shall see, however, many important ethylene-containing polymers are copolymers. Nomenclatures for various types of polyethylene are addressed in section 1.3. Though some have suggested that its name implies the presence of unsaturated carbon atoms, there are in fact few C=C bonds in polyethylene, usually less than 2 per thousand carbon atoms and these occur primarily as vinyl or vinylidene end groups. 

Li, J., Zhao, Q.L., Chen, J.Z., Li, L., Huang, J., Ma, Z., et al. Highly ordered microporous films containing a polyolefin segment fabricated by the breath-figure method using well-defined polymethylene-b-polystyrene copolymers. Polym. Chem 1, 164—167 (2010)... 

An interesting exploitation of the OH side groups borne by these copolymers is provided by a recent study in which poly(a-terpineol-co-MMA) was modified by grafting phenyl benzoate mesogenic groups, bearing vinyl terminated polymethylene spacers, to give liquid crystalline materials [88]. 

From the chemical point of view, POs are simple materials composed of C and H. However, the configuration diversity of even the simplest polymethylene results in a spectrum of properties. The situation becomes more complex for polymers of the general formula (C H2 )dp where n>3 and the degree of polymerization, DP, is large. The next level of complexity is encountered with blends and copolymers, e.g., poly(ethylene-co-n-olefin) or poly(propylene-co-n-olefin). However, today the ultimate challenge for characterization is found in POs obtained during multi-catalyst/multi-reactor/multi-monomer polymerization processes. 

The letter M designates that the ethylene propylene has a saturated polymer chain of the polymethylene type, according to the ASTM.12 EPM (copolymer of ethylene and propylene) rubber and EPDM (terpolymer of ethylene, propylene, and a nonconjugated diene) with residual side chain unsaturation, are subclassified under the ASTM M designation. 12... 

Although the electrostatic force plays the main role in the interactions of oppositely charged surfactants and polymers, hydrophobicities of polymer and surfactant also play a role. Zana and Benrraou (2000) studied the interaction of two polyelectrolytes PSl and PS4 (copolymers of disodium maleate and methyl or butyl vinyl ether, respectively), and quaternary ammonium bromide surfactants (3-dodecyldimethyl(alkyl)ammonium bromides and two dimeric surfactants of the polymethylene-a,fi)-bis(dodecyldimethylammonium bromide) type). They used the surfactant-binding isotherms method and spectrofluorometry using pyrene as a fluorescent probe to detect the onset of binding. Their results showed that surfactant binding to the polymer is more pronounced when the polymer is more hydrophilic for a given surfactant. 

Fig, 6. Chain conformation and symmetry elements for a) Isotactic alternate copolymer of ethylene and bute ne-2. b) Polymethylene,... 

In this review, we describe the polyhomologation reaction, a living polymerization that results in the synthesis of linear polymethylene with no branches, controlled molecular weight, narrow molecular-weight distribution, well-defined topology and functionality. Polymethylene is a unique member of the polyethylene family. The carbon backbone is built up one carbon at a time, in contrast to the two carbons in ethylene polymerization (Jellema et al., 2010). The polyhomologation reaction can provide polymethylene samples for model studies of structure-property relationships and functionalized polymethylene for copolymers that can function as polyethylene compatibilizers. In addition, since many vinyl compounds do not readily polymerize, the polyhomologation reaction can serve as an entry to completely new substances. 

The formation of PM-PDMS-PM triblock copolymer aggregates is a kinetic rather than thermodynamic process (Wang et aL, 2007). Micrometer-sized crystal plates are produced if the sample solution is cooled slowly, while nanodiscs are formed when the hot polymer solution is quenched with water. Given sufficient time, polymethylene chains may be reorganized to form the larger crystal plates. 

Chen, J.Z., Zhao, Q.L., Shi, L.P. et al. (2009) Synthesis, structure, and property of well-defined polymethylene-based diblock copolymers by a combination of Uving polymerization of yhdes and atom transfer radical polymerization. Journal of Polymer Science Part A Polymer Chemistry, 47,5671-5681. 

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