Poly Rubber Compounding

Ghoreishy, M. H. R. and Nassehi, V., 1997. Modelling the transient flow of rubber compounds in the dispersive section of an internal mixer with slip-stick boundary conditions. Adv. Poly. Tech. 16, 45-68. 

Since 1960, the inner core has been made from c/5-poly-butadiene by the compression moulding technique. This replaced the earlier material made from a suspension of barytes or bentonite clay in water and glycerine or the winding of rubber threads made from t /5-polyisoprene, either from latex or a dry rubber compound. A typical thread recipe is given Table 4. 

Plasticiser/oil in rubber is usually determined by solvent extraction (ISO 1407) and FTIR identification [57] TGA can usually provide good quantifications of plasticiser contents. Antidegradants in rubber compounds may be determined by HS-GC-MS for volatile species (e.g. BHT, IPPD), but usually solvent extraction is required, followed by GC-MS, HPLC, UV or DP-MS analysis. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out. The determination of antioxidants in rubbers by means of HPLC and TLC has been reviewed [58], The TLC technique for antidegradants in rubbers is described in ASTM D 3156 and ISO 4645.2 (1984). Direct probe EIMS was also used to analyse antioxidants (hindered phenols and aromatic amines) in rubber extracts [59]. ISO 11089 (1997) deals with the determination of /V-phenyl-/9-naphthylamine and poly-2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ) as well as other generic types of antiozonants such as IV-alkyl-AL-phenyl-p-phenylenediamines (e.g. IPPD and 6PPD) and A-aryl-AL-aryl-p-phenylenediamines (e.g. DPPD), by means of HPLC. 

Polymers. In combination with various metal salts, sorbitol is used as a stabilizer against beat and light in poly(vinyl chloride) (qv) resins and, with a phenolic antioxidant, as a stabilizer in uncured styrene—butadiene mbber (qv) compositions and in polyolefins (see He AT STABILIZERS Olefin polymers Rubber compounding). Heat-sealable films are prepared from a dispersion of sorbitol and starch in water (255). Incorporation of sorbitol in collagen films gready restricts their permeability to carbon dioxide (256). 

Starch poly(ethyleniminothiourethanes) prepared by the reaction of SX with poly(ethylenimine) were shown to be suitable reinforcing agents for rubber compounds.79,80 Master batches were prepared using SX with DS values ranging from 0.08 to 0.58 and starch contents of 15 to 50 phr. Best results were obtained at a DS of —0.22 and a loading of 25 phr starch, with a PEI stoichiometric ratio of 3.5. Hardness generally increased with DS and starch content, while compression set and abrasion resistance decreased. 

ANTIMONY SESQUIOXIDE (1309-64-4) Ignites and burns in heated air above 420°F/215°C. Violent reaction with bromine trifluoride. Reacts with chlorinated rubber, alco-hols/glycols, organic and a-hydroxy acids (fruit acids), o-dihydric phenols, polyethylene glycol, and other poly hydroxy compounds. 

ASTM D2151, Staining of poly(vinyl chloride) compositions by rubber compounding ingredients. 1995. 

ASTM D2151-95(2000) Standard Practice for Staining of Poly(Vinyl Chloride) Compositions by Rubber Compounding Ingredients... 

Compound, caulking, conductive Compound, polyurethane Compound, heat sink, silicone Compound, sealing, poly sulfide rubber Compound, plastic polyurethane Primer, silicone rubber sealant Primer, polyurethane Primer, silicone... 

Isoprene is a so-called poly-functional monomer the molecule contains two unsaturated double bonds between carbon atoms that are able to form cross-linking to other molecules by a polymerization process. Natrual rubber, for example, is a poly-isoprene compound formed by polymerization of isoprene molecules of the chemical formula CsHs. Calculate the molar mass M of isoprene ... 

In contrast to the small amounts of antioxidant in raw rubber, compounded rubber often contains several percentages of protective material. It seems contradictory at first that antioxidants can continue to be very effective even after the polymer system has undergone a high-tanperature, oxidative cross-linking. A case in point is poly(vinyl ethyl ether) CToss-Unked by dicumyl peroxide ... 

Oxidized castor oils are excellent nonmigrating, nonvolatile plasticizers (qv) for ceUulosic resins, poly(vinyl butyral), polyamides, shellac, and natural and synthetic mbber (see Rubber, natural). The high viscosity products are also used as tackifiers in gasket compounds and adhesives (qv) because of good oil and solvent resistance. They also serve as excellent pigment grinding media and as a base for inks (qv), lubricating oils, and hydrauHc oils (62). 

In an acetone extract from a neoprene/SBR hose compound, Lattimer et al. [92] distinguished dioctylph-thalate (m/z 390), di(r-octyl)diphenylamine (m/z 393), 1,3,5-tris(3,5-di-f-butyl-4-hydroxybenzyl)-isocyanurate m/z 783), hydrocarbon oil and a paraffin wax (numerous molecular ions in the m/z range of 200-500) by means of FD-MS. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out (Chapter 2). The method of Dinsmore and Smith [257], or a modification thereof, is normally used. Mass spectrometry (and other analytical techniques) is then used to characterise the various rubber fractions. The mass-spectral identification of numerous antioxidants (hindered phenols and aromatic amines, e.g. phenyl-/ -naphthyl-amine, 6-dodecyl-2,2,4-trimethyl-l,2-dihydroquinoline, butylated bisphenol-A, HPPD, poly-TMDQ, di-(t-octyl)diphenylamine) in rubber extracts by means of direct probe EI-MS with programmed heating, has been reported [252]. The main problem reported consisted of the numerous ions arising from hydrocarbon oil in the recipe. In older work, mass spectrometry has been used to qualitatively identify volatile AOs in sheet samples of SBR and rubber-type vulcanisates after extraction of the polymer with acetone [51,246]. 

This group of synthetic elastomers is better known under the trade name ThiokoP. Polysulphide rubbers are condensation polymers of sodium poly sulphide and dichloro-compounds they have outstanding resistance to swelling by oils and solvents but tensile strength is... 

Fluorosilicate glass-ceramics, 12 634-637 Fluorosilicates, 12 631 Fluorosilicone bases, 20 243 Fluorosilicone blends, 20 247 Fluorosilicone compounds, 20 243 Fluorosilicone rubber, 20 246—247 Fluorosilicones, 20 241 21 772. See also Poly(fluorosilicones)... 

Heat-Sensitizing Process. Another process used to make latex rubber articles of thicker section involves sensitizing the compound so that it coagulates when heated to a given temperature, then using heated molds to build the article to the desired thickness. Ammonia-preserved latex is used in this process, and polyether, polythioether, or poly(vinyl methyl ether) (PVME) can be used as heat-sensitizing agents. 

It is possible to cross-link polyisobutylene and poly(isobutylene-isoprene) and chlorobutyl rubber by means of certain additives however, the physical properties of the vulcanizates prepared by conventional curing methods cannot be attained. The most promising results were obtained with chlorobutyl compounds containing thioether polythiols as prorads. ... 

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