Resins, properties processing

The reaction is completed after 6—8 h at 95°C volatiles, water, and some free phenol are removed by vacuum stripping up to 140—170°C. For resins requiring phenol in only trace amounts, such as epoxy hardeners, steam distillation or steam stripping may be used. Both water and free phenol affect the cure and final resin properties, which are monitored in routine quaHty control testing by gc. OxaHc acid (1—2 parts per 100 parts phenol) does not require neutralization because it decomposes to CO, CO2, and water furthermore, it produces milder reactions and low color. Sulfuric and sulfonic acids are strong catalysts and require neutralization with lime 0.1 parts of sulfuric acid per 100 parts of phenol are used. A continuous process for novolak resin production has been described (31,32). An alternative process for making novolaks without acid catalysis has also been reported (33), which uses a... 

Ease of cure, easy removal of parts from mold surfaces, and wide availabiHty have made polyesters the first choice for many fiber-reinforced composite molders. Sheet mol ding compound, filament winding, hand lay-up, spray up, and pultmsion are all weU adapted to the use of polyesters. Choosing the best polyester resin and processing technique is often a challenge. The polyester must be a type that is weU adapted to the processing method and must have the final mechanical properties requked by the part appHcation. Table 1 Hsts the deskable properties for a number of fiber-reinforced composite fabrication methods. 

Polyester carbonate resins are made by the interfacial process described for standard PC resins. The phthalate units are introduced by reaction of the appropriate phthaloyl dichlorides concurrent with the phosgenation. At present, Bayer, GE, and Miles produce polyester carbonate resins (47) sales volume is low, probably ca 100 t/yr. Polyester carbonates are used primarily in appHcations requiring 5—25°C higher heat-deflection temperature and better hydrolytic performance than are provided by standard PC resins. Properties are given in Table 9. 

Figure 7 illustrates the use of HPGPC to aid a resin chemist in developing an in-house isocyanate crosslinker for a powder coating system. Isocyanate crosslinker X-02 gave desired properties and is considered the standard. At the early stage of the development, resin X-03 was initially made. By changing the types of reactants, molar ratio of reactants and reaction conditions, resin X-36 was the next iteration in the resin synthesis process. Finally, X-36 was fine-tuned to produce X-38 which matched X-02 in both its chemical reaction properties and its MWD. 

Paint technologies, 18 54-55, 56 Paint viscosity, measuring, 18 69 Paired comparison test, 11 512 Paired synthesis, of phthalide and 4.4-butylbenzaldehyde, 9 680-681 PAI resins, properties of, 10 215t Pair production process, 21 313 Palatinit, 12 44... 

In summary an FDEMS sensor system can be used to monitor the processing properties in situ during the fabrication process of a composite part. A smart sensor control system can be used to monitor resin properties for reproducability-quality assurance, to ensure fabric impregnation, and to control and optimize the composite fabrication process intelligently through in situ sensor feedback. 

A comparatively large selection of thioureas can be formed from the reaction of amines with isothiocyanates, hence they are attractive starting materials for formation of guanidines. A common solution-phase approach to this reaction involves abstraction of the sulfur via a thiophillic metal salt, like mercuric chloride.10 For solid-phase syntheses, however, formation of insoluble heavy-metal sulfides can have undesirable effects on resin properties and on biological assays that may be performed on the product. A more relevant strategy, with respect to this chapter, is S-alkylation of thioureas and then reaction of the methyl carbamimidothioates formed (e.g., 5, Scheme 6) with amines. This type of process has been used extensively in solution-phase syntheses.1 Ul4 Two examples are shown in Scheme 6 11 the second is an intramolecular variant, which involves concomitant detrity-lation.15... 

Pultrusion [PHENOLIC RESINS] (Vol 18) [PLASTIC PROCESSING] (Vol 19) [REINFORCED PLASTICS] (Vol 21) [COMPOSITEMATERIALS - SURVEY] (Vol 7) resin properties required for [COMPOSITE MATERIALS - POLYMER-MATRIX - THERMOSETS] (Vol 7)... 

Epoxy vinyl ester resins are a special class of unsaturated resin. This resin is made by capping an epoxy resin with methacrylic acid and then dissolving in styrene monomer to the desired viscosity. This gives mechanical properties similar to epoxy resins, but the processibility (low viscosity allowing for resin infusion processes) of an unsaturated polyester resin. As with unsaturated vinyl esters, the most common fire retardant vinyl ester resin is based on a resin made from a halogenated system, tetrabromobisphenol A. The level of bromine in the resin and the presence of antimony will determine the fire performance of the resin. These resins are normally used for corrosion resistant equipment or when fire performance and high mechanical properties are required. It is very difficult to get a low smoke value with a brominated vinyl ester resin again due to the fact that bromine... 

This chapter is designed to provide a basic understanding of the synthetic resin (plastics) processing that is necessary to improve or alter the properties of various synthetic resin materials so these resins may be turned into more desirable and useful consumer products. It also discusses the health, safety, and environmental issues associated with the industrial processes used to formulate colorant and additive products. 

It is beyond the scope of this review to discuss in detail viscoelastic properties at and after gelation. The gel point is one of the important characteristics in the epoxy resin curing process from both kinetic and rheological aspects. The gelation transition has been widely studied for epoxy resin systems [39,44,133-138] and already discussed in some of this series, such as by Malkin and Kulichikhin [28], Williams et al. [139], and Winter and Mours [140]. Rheological techniques for the determination of the gel point have been summarized for thermosetting resins by Halley et al. [29,141]. 

The modified-classical phenolic resins are particularly noteworthy for their effect on the mechanical and thermal properties of the cured resin. The processing of these systems is very similar to the classical systems. The nonclassical phenolic resins utilize phenol, but in many cases give a cured product with a chemical structure having little resemblance to the classical system. In future articles, it would be best to develop independent grouping for addition-cure phenolics resins. This redefinition of polymer types is not within the scope of this entry and instead, this interesting class of polymers has been viewed based on current designations. 

Polyolefin - Polyolefins are a large class of carbon-chain elastomeric and thermoplastic polymers usually prepared by addition (co)polymerization of olefins or alkenes such as ethylene. The most important representatives of this class are polyethylene and polypropylene. There are branched and linear polyolefins and some contain polar pendant groups or are halogenated. Unmodified polyolefins are characterized by relatively low thermal stability and a nonporous, nonpolar surface with poor adhesive properties. Processed by extrusion, injection molding, blow molding, and rotational molding. Other thermoplastic processes are used less frequently. This class of plastics is used more and has more applications than any other. Also called olefinic resin, olefinic plastic. 

Lamellar dispersion of polyamide domains within HDPE matrix has been achieved by proper choice of rheology of the resins and processing conditions [Subramanian, 1985]. The platelet shape of PA domains enhanced its barrier properties against permeation by gases or liquids. The technology was commercialized and marketed by DuPont (Selar RB), aiming at packaging applications... 

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