Polyphenylene resin

In 1968 the Monsanto Company announced the availability of novel soluble low molecular weight polyphenylene resins. These may be used to impregnate asbestos or carbon fibre and then cross-linked to produce heat-resistant laminates. The basic patent (BP 1037111) indicates that these resins are prepared by heating aromatic sulphonyl halides (e.g. benzene-1,3-disulphonyl dichloride) with aromatic compounds having replaceable nuclear hydrogen (e.g. bisphenoxy-benzenes, sexiphenyl and diphenyl ether). Copper halides are effective catalysts. The molecular weight is limited initially by a deficiency in one component. This is added later with further catalyst to cure the polymer. 

Cold wall heats of ablation values ranged between 7700 and 13,800 Btu/lb. The best performance was obtained with the heterocyclic polyimide and polybenzimidazole and the aromatic polyphenylene resins, all of which exceed the heat of ablation for the widely used phenol formaldehyde (phenolic) resin. The superior charring characteristics of these polymers contributed greatly to their high heats of ablation. The various plastic materials, with their inherently low thermal conductivities, greatly restricted the flow of heat from the surface region into the specimen substrate. 

The cyclotrimerization of ethynylbenzene leads to 1,3,5-triphenylbenzene, and consequently polycyclotri-merization of bisethynylbenzene yields a high temperature stable polyphenylene resin.3° This chemical concept has been extended to develop the first ethynyl-terminated polyimide in the literature. " The following figure [7] outlines the synthetic route characterized by simply replacing some of the aromatic diamine with an ethynyl-substituted aromatic monoamine to provide a ethynyl-terminated polyimidf resin. 

For many years there has been a demand for rigid plastics materials which could withstand temperatures of 250°C and at the same time have good oxidation and water resistance coupled with ease of processability and reasonable cost. Such a demand led in the late 1960s to the small-scale production of a number of polymers which could be considered as being intermediate between polyphenylene, Figure 23.24, and the commercial phenolic resins. 

Amongst the important heat-resisting cross-linked polymers are the phenolic resins (chapter 23), the Friedel-Crafts resins (also Chapter 23), the polyphenylenes (Chapter 21) and certain polysulphides (also Chapter 21). One problem of these materials is that they tend to be brittle. This is overcome in part... 

Cellulose Esters Epoxy Resins Lignins Polystyrene Poly (2-vinyl pyridine) Polyvinyl Chloride Polymethyl methacrylate Polyphenylene Oxide Phenolics Polycarbonate Polyvinyl Acetate, etc. Polyvinyl butyral SBR rubber, etc., etc. 

Polyacetal Homopolymer Polyelherimide Phenolic Resin Polypropylene Polyvmylidene Difluonde Polyphenylene Oxide Polyphenylene Oxide (Glass Filled) Polyethersulphone I ill ll I i jH... 

Polyphenylene sulfide Toughen brittle resins, +Can impart special properties such... 

Polyphenylene oxide and polyphenylene ether are oxides or ethers like polyoxymethylene but an aromatic unit replaces the methylene group leading to — ( — C6H4 — O—) — Polyphenylene ether has too high a glass transition temperature to be easily processed and is marketed in the form of alloys with other resins, such as ... 

For the past 20 years, 1,4-dichlorobenzene has been used principally (35-55% of all uses) as a space deodorant for toilets and refuse containers, and as a fumigant for control of moths, molds, and mildews. A significant amount of 1,4-dichlorobenzene is exported (34%), with lesser amounts used in the production of polyphenylene sulfide (PPS) resin (approximately 27% of its total use), and as an intermediate in the production of other chemicals such as 1,2,4-trichlorobenzene (approximately 10%). Minor uses of 1,4-dichlorobenzene also include its use in the control of certain tree-boring insects and ants, and in the control of blue mold in tobacco seed beds (Chemical Marketing Reporter 1990 HSDB 1998). 

Production, Import/Export, Use, Release, and Disposal. Data on the production and uses of 1,4-dichlorobenzene in the United States are available (C EN 1995 Chemical Marketing Reporter 1990 HSDB 1998 IRPTC 1985 SRI 1996 TRI96 1998). Production has increased over the past decade and is projected to increase for the next several years due to an increased demand for 1,4-dichlorobenzene to be used in the production of polyphenylene sulfide (PPS) resins. Incineration is the recommended disposal method for 1,4-dichlorobenzene (HSDB 1998 IRPTC 1985). Disposal of this compound is controlled by... 

The primary resin of interest is epoxy. Carbon-fiber-epoxy composites represent about 90% of CFRP production. The attractions of epoxy resins are that they polymerize without the generation of condensation products that can cause porosity, they exhibit little volumetric shrinkage during cure which reduces internal stresses, and they are resistant to most chemical environments. Other matrix resins of interest for carbon fibers include the thermosetting phenolics, polyimides, and polybismaleimides, as well as high-temperature thermoplastics such as polyether ether ketone (PEEK), polyethersulfone (PES), and polyphenylene sulfide. 

Many semicompatible rubbery polymers are added to increase the impact resistance of other polymers, such as PS. Other comminuted resins, such as silicones or polyfluorocarbons, are added to increase the lubricity of other plastics. For example, a hot melt dispersion of polytetrafluoroethylene (ptfe) in polyphenylene sulfide (PPS) is used as a coating for antistick cookware. 

Matrix materials for commercial composites are mainly liquid thermosetting resins such as polyesters, vinyl esters, epoxy resins, and bismaleimide resins. Thermoplastic composites are made from polyamides, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polysulfone, polyetherim-ide (PEI), and polyamide-imide (PAI). 

Electroconductive resin compositions, which are useful for packaging electronic devices, have been described. In general, electroconductive resin compositions are made up from a thermoplastic resin and an electroconductive filler, mostly carbon black. Polyphenylene ether) resins are known to impart heat resistance. For general purposes, a poly(styrene) (PS) resin and an ABS resin are superior to other resins in that even if carbon black is incorporated in a large amount, there will be no substantial decrease in the flowability or... 

A family of engineering thermoplastics based on the above technology includes PPO polyphenylene oxide, Noryl thermoplastic resins (modified... 

The fracture energy GIc of unsaturated polyesters (UP), vinyl esters (VE), and phenolic resins, is less than 200 Jm 2 at room temperature. Epoxy networks can exhibit higher values but always lower than those of thermoplastics of similar Tg, as polycarbonate, polyetherimide, or polyphenylene ether. 

Polyphenylene oxide. Oxidative polymerization of 2,6-xylenol to the engineering resin polyphenylene oxide (PPO) is catalyzed by copper and manganese amines. Pyridine is a typical amine used in the polymerization. 

Polyphenylene sulfide parts are commonly bonded together with adhesives. A suggested surface preparation method is to solvent-degrease the substrate in acetone, sandblast, and then repeat the degreasing step with fresh solvent. The polyphenylene sulfide surface that forms next to a mold surface is more difficult to bond than a freshly abraided surface. This is possibly due to a different chemical surface structure that forms at high temperature when the resin is in contact with the metal mold surface. 

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