Glass transition temperature polyketones

Fluorinated phthalide 297 has been used to prepare polyketones such as 298, by polymerization with bisphenol A 299. This example has a glass transition temperature of 215 °C and forms strong transparent films. Remarkably, this is a polymerization based on an aromatic substitution reaction (SN2Ar) <1997MC210>. 

More interestingly perhaps, the polyketone 7, derived from bis(4-phenoxyphenyl)-p-carborane (3) and biphenyl-4,4 -dicarboxylic acid (4), is essentially amorphous on isolation from trifluoromethanesulfonic acid, but crystallises on heating above its glass transition temperature (267 °C) before finally melting at around 390 °C. 

As previously mentioned, the properties of olefm-CO copolymers depend strongly on the nature of the olefin employed. The glass transition temperature of 1-olefin-CO copolymers decreases from room temperature to nearly -60 °C upon increasing the chain length of the 1-olefin from propylene to 1-dodecene [33]. By contrast to polar ethylene-CO copolymers, copolymers with higher l-olefins display a hydrophobic character. For 1-olefin copolymerization, catalysts with entirely alkyl-substituted diphosphine hgands R2P-(CH2) -PR2 (R=alkyl, by comparison to R=Ph in dppp) such as 3 are particularly well-suited [48]. Efhylene-l-olefin-CO terpolymers and 1-olefin-CO copolymers can be prepared in aqueous polymerizations [43, 47, 48]. In the aforementioned copolymerization reactions, the polyketone was reported to precipitate during the reaction as a sohd [45, 47, 48, 50]. However, in the presence of an emulsifier such as sodium dodecyl sulfate (SDS) and under otherwise suitable conditions, stable polymer latexes can be obtained. 

The S5mthesis of aromatic high-molecular polyketones by the low-temperature solid-state polycondensation of 4,4 -bisphenoxybenzophenone and isophthaloylchloride in the presence of AICI3 in 1,2-dichlorethane is possible [337]. Obtained pol miers are thermoplasts with glass transition temperature 160 °C and melting point 382 °C. 

The aromatic polyketones without ester bonds can also be produced by the polymerization of bis(chlorbenzoyl)dimethoxybisphenyls in the presence of nickel compounds [341]. The polymers have the high molecular mass, the amorphous stmcture, the glass transition temperature 192 °C and 218 °C and form abiding flexible films. 

It is reported [403] on liquid-crystal polyenamineketone and on mix of liquid-crystal thermotropic copolyester with polyketone [404]. The mix is prepared by melts mixing. It has been foimd that the blending agents are partially compatible the mixes reveal two glass transition temperatures. 

For example, the method for production of aromatic polyketones by means of Friedel-Craft polycondensation of bis (arylsilanes) with chlorides of aromatic dicarboxylic acids (isophthaloyl-,terephthaloyl-,4,4 -oxydibenzoylchloride) at 20 °C in environment of dissolvent (1,2-dichlor-ethane) in the presence of aluminum chloride is proposed in Ref [331], The polyketones have the intrinsic viscosity more than 0.37 deciliter/gram (at 30 °C, in concentrated H SO ), glass transition temperature is 120-231 °C and melting point lies within 246-367 °C. The polyketones start decomposing at a temperature of 400 °C, the temperature of 10% loss of mass is 480-530 °C. 

The material can be melt processed because of the ether linkages present in the backbone of the polymer, but it stiU maintains properties similar to those of the polyimides. The high-temperature resistance of the polymer allows it to compete with the polyketones, polysulfones, and poly(phenylene sulfides). The glass transition temperature of PEI is 215°C. The polymer has very high tensile strength, a UL temperature index of 170°C,... 

It will be clear that the mechanical properties of polyketones at ambient temperatures are sensitive for these ageing and these moisture absorption effects especially due to the presence of the glass-rubber transition in that temperature region. The influence of both effects is in general opposite to each other the stiffness increases due to ageing and decreases due to moisture absorption. Moisture absorption effects are time and object dimensions dependent whereas ageing effects are only time dependent. 

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