Resins crosslinked

This is also known as Bulk Moulding Compound (BMC). It is blended through a mix of unsaturated polyester resin, crosslinking monomer, catalyst, mineral fillers and short-length fibrous reinforcement materials such as chopped glass fibre, usually in lengths of 6-25 mm. They are all mixed in different proportions to obtain the required electromechanical properties. The mix is processed and cured for a specific time, under a prescribed pressure and temperature, to obtain the DMC. 

The free volume model seems to be more adequate to describe the plasticization behaviour of the systems of lower amine content. According to Eq. (5), the higher is the change of the expansion coefficient the lower is the influence of the diluent volume fraction. The three TGDDM-DDS mixtures cured with 20, 30 and 50 PHR of hardener were characterized l2) by changes of the expansion coefficient at the glass transition, respectively, of 0.63, 1.08 and 2.94x 10 3 °C l. The more dense and stiffer resin crosslinked with 50 PHR of DDS should be, in principle, the less... 

There are over 400 different commercial alkyd resin formulations based on phthalic anhydride used in the coatings business. Alkyd resins for paints are made by reacting phthalic anhydride with a poly-alcohol (usually from naturally occurring sources rather than synthetic) that contains unreacted double bonds. The paint dries by the resin crosslinking through reaction of the double bonds under the influence of oxygen in the air. 

In alkaline and acid solutions, thermosets containing ester groups are degrated mainly due to the hydrolysis of the esters (1-6) But in case of the resin crosslinked by ester bonds such as some epoxy resins (7-9). corrosion behavior is though to be different from that of the resin which has ester bonds in the main chain. 

The leading solid phases are the 2-chlorotrityl chloride resins. Professor K. Barlos (University of Patras, Greece) has made the single most important contribntion to the development of these resins. They consist of a polystyrene-base resin crosslinked with a small amonnt of divinylbenzene and functionalized with 2-chlorotritiyl chloride. 

Gregor et al66 reported the Cu-complex formation of poly(methacrylic acid) (PMA) resins crosslinked with 1% or 9% divinylbenzene. The formation constants of the Cu complexes with the resins were smaller than that of noncrosslinked PMA. The stepwise formation constants decreased from Ki to KA in the resin system, which was the opposite of the noncrosslinked PMA system. The rigidity of the polymer-ligand chain was considered to hinder chelate formation. Formation constants of the PMA resin were also reported by Gustafson era/.67. The formation constant of the noncrosslinked PMA decreased for various metal ions ... 

Poly(ethyleneimine)(PEI) bridged by alkylene dihalide has been used as a chelating resin for Cu and Co68. Dingman et al,69 studied the adsorption of metal ions on PEI resins crosslinked with toluene diisocyanate. The amount of metal ions adsorbed decreases with the degree of crosslinking. These crosslinked PEI resins... 

The control resin network used in this study was a diglycidyl ether-based epoxy resin crosslinked with a cycloaliphatic diamine. Cooligomeric modifiers were prepared having varying percentages of TFP and DP siloxane and aminoethylpiperazine end groups. Both siloxane and ATBN and CTBN elastomers were used as epoxy modifiers, the latter two having been included to facilitate direct comparisons between modifiers in similarly prepared networks. 

Figure 6.2.15. Result for a Py-GC/MS analysis of Wang polystyrene resin crosslinked with poly(ethylene glycol)(16) and having 0.8-1.5 mmol/g 4-benzyloxybenzyl alcohol (upper trace) and the pyrogram of polystyrene (lower trace). Pyrolysis done at 60(f C in He, with the separation on a Carbowax type column.

Resins/Crosslinking Agent Epoxy/Alkyd Solids, %... 

Phenol-formaldehyde (PF) resins have been used as model compounds for the study of pyrolysis and combustion reactions that occur in solid fuels [10]. Utilising these resins it is possible to incorporate a wide range of heteroatomic and hydrocarbon moieties to simulate compounds that arise naturally in the solid fuels. A series of phenol resins crosslinked with thiophene, dibenzo-thiophene, diphenylsulfide, benzyl phenyl sulfide, thioanisole, 8-hydroxyquin-oline and 2-hydroxycarbazole were synthesised. These samples were then cured at 200°C (Fig. 15.2.1) and the resulting resins examined by solid-state NMR spectroscopy. The C CP/MAS spectra of a standard PF resin is shown... 

Natural polymers crosslinked by synthetic molecules represent many resins used for industrial applications. These are now being more closely examined by solid-state NMR spectroscopy to try to understand more fully what occurs in these systems and how it is possible to improve them. Of industrial importance are the polyphenolic tannin resins crosslinked by hexamethylenetetramine. These principally contain flavan-3-ols (Fig. 15.2.18) in the tannin [21] and have been examined by CP/MAS solid-state NMR spectroscopy. Hexamethylenetetramine was used in preference to formaldehyde as it has showed a much faster rate of reaction. The intermediates in this reaction are tribenzyl-, dibenzyl-<(>, and monobenzylamines some of which rearrange to give the dihydroxydiphenylmethane crosslinking bridges in the resin. The exact nature of the crosslinking process, however, is still in debate and the study was undertaken to try and clarify the issue. To examine this process fully, a comparison was made between pine tannin (high in flavan-3-ol) (Fig. 15.2.19) pine tannin hardened with paraformaldehyde (Fig. 15.2.20) and pine tannin hardened with hexamethylenetetramine (Fig. 15.2.21). 

Cadox . [Akzo] Organic peroxide compds. initiator to curing polyester resins crosslinking agent to curing silicone rubbers. 

Cymel. [Am. Cyanamid] Melamine resins crosslinking agent for cationic resins, emulsions, coating systems, electroplating, industrial finishes. 

Esperfoam . [Witco/Argus] Peroxide derivs. initiator for polymerization of ethylene, styrene, acrylates, curing of unsat. polyester resins crosslinking agent for chlorinated polyethylene. 

SP-. (Schenectady] Phenolic resins crosslinking agent, tackifier, plasticizer for rubber compds., adhesives, and sealants. 

Decomposition of organocyclosilazanes occurs with many reagents The polymerization of (SiN)— rings does not occur as easily as the polymerization of (SiO)— rings. In attempts to polymerize cyclosilazanes with basic catalysts, waxy and resinous crosslinked polymers are formed " , but tricyclic compounds as well . 

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