The fire retardancy, thermal and thermomechanical properties of PP/polycarbonate(PC) blends prepared using polyolefins grafted with functional groups as compatibilisers were studied. The effect of compatibiliser on the morphology was correlated with the thermomechanical properties. The blends containing 75% PP and 25% PC or 22% PC plus 3% compatibiliser were prepared by melt processing in a mixer. The compatibilisers were PP-g-maleic anhydride(MA) and an ethylene/acrylic/MA terpolymer(EBuAMA). The thermal stability was improved up to 400C when using compatibiliser in comparison with pure PP/PC blend. The thermomechanical properties were improved for PP/PC/PP-g-MA blend. It was found that the addition of compatibiliser slightly decreased the particle size of the minor PC phase. The crystallisation temperature of PP in PP/PC/PP-g-MA increased, which could explain the improvement of the properties of the blend in comparison with PP/PC/EBuMA. Fire retardant formulations were also developed. The fire retardant properties of the blend were shown to be gradually affected by the presence of a compatibiliser. 34 refs.

Brominated flame retardants may undergo thermal decomposition at temperatures lower than those of polymer combustion. Decabromodiphenyl ether, the main subject of this study, exhibited a threshold decomposition temperature that was close to PP processing temperatures. In the presence of hydrocarbon polymer, the loss of bromine led to the formation of lower brominated by-products and hydrobromic acid. The latter attacked stabiliser package components, hindered amine light stabilisers(HALS) in particular. The aminium hydrobromide salt thus formed is well known to be inefficient as a stabiliser. It was found in this study that it was less thermally stable than the parent amine. In the case of PP, it was demonstrated that excessive processing temperature of polymer containing polybrominated aromatic flame retardant and HALS resulted in an irreversible loss of the light stabiliser from the very beginning of the material's service life. 17 refs.

Photochemical decomposition of decabromodiphenyl ether(I) induced by 300 to 400nm light is known to be a radical process leading to the formation of HBr, provided that there is a hydrogen donor(RH) in the system. The stepwise debromination of the aromatic ring was shown to take place, giving rise to lower brominated diphenyl ethers with a number of by-products. The hydrogen donor was converted to a corresponding R-Br derivative in this process. Free HBr was prone to photolytic decomposition, particularly at more advanced stages of conversion of I. It was demonstrated, for the case of PP, that the radicals thus formed could participate actively in the initiation step of polyolefin chain oxidation. In the presence of hindered amine light stabiliser(HALS), the HBR formation through photolysis of I was enhanced while the formation of R-Br was totally suppressed. The rate of disappearance of I was, however, not influenced by the HALS. The causes of the detrimental effect of brominated diphenyl ethers on the polymer UV resistance were examined. 25 refs.

Tri(acryloyloxyethyl)phosphate(TAEP) was blended with methacrylated phenolic melamine(MAPM) in different ratios to give a series of UV-curable intumescent flame retardant resins. The cured TAEP/MAPM samples expanded significantly when burning. The expansion behaviour and flame retardance of the cured resins were characterised by the volume ratio after and before combustion and by limiting oxygen index(LOI). A distinct synergistic effect was found between TAEP and MAPM. The TAEP-0.30MAPM sample exhibited the highest degree of expansion and the highest LOI value. The degradation was monitored by TGA and in-situ FTIR spectroscopy. A degradation mechanism was proposed in which the phosphate group in TAEP first degraded to form polyphosphoric acids, which further catalysed the degradation of the material to form char with emission of nitrogen volatiles from MAPM, leading to the formation of expanding char. The morphological structures of crusts of the formed chars were observed by SEM, which demonstrated the synergistic effect between TAEP and MAPM. 22 refs.

Polyamides and polyurethanes were prepared by reaction of N-tetrachlorophthalimidosuccinic acid or its diol derivatives with different diisocyanates. The synthetic procedures for preparation of monomers, model compounds and polymers are described, together with their chemical structures as characterised by FTIR and PMR spectroscopic techniques. The physical properties of polymers, including intrinsic viscosity, solubility properties, thermal behaviour, thermal stability and flame resistance, were also studied. The results showed that the incorporation of the pendent N-tetrachlorophthalimide group into polyamide and PU backbones increased the thermal stability and the flame resistance compared with the unmodified analogous compounds. 20 refs.

Phosphorus-containing epoxy systems were prepared from isobutylbis(hydroxypropyl)phosphine oxide(IHPO, Cyagard RF1243) and DGEBA. Diethyl-N,N-bis(2-hydroxyethyl)aminomethyl phosphonate(Fyrol 6) could not be incorporated into the epoxy backbone by a reaction with either epichlorohydrin or DGEBA because intramolecular cyclisation took place. The curing behaviour of the IHPO-DGEBA prepolymer with two primary amines was studied and materials with moderate Tgs were obtained. V-0 materials were obtained when the resins were tested for ignition resistance using the UL-94 test. 14 refs.

The flame retardant and mechanical properties of rubber-modified, aluminium hydroxide filled PP were studied, together with its morphology. The PP was toughened with EPDM and zinc neutralised sulphated EPDM ionomer. The PP matrix, when high filled with aluminium hydroxide particles can achieve an adequate level of flame retardancy, but there is a decrease in the mechanical properties due to an inadequate adhesion between the aluminium hydroxide particles and the PP matrix, and also the tendency for the filler to agglomerate. By using zinc neutralised sulphated EPDM ionomer instead of EPDM the tensile properties were shown to improve with only a slight decrease in toughness, due to improvements in the interfacial adhesion between modifier and matrix. SEM micrographs showed that the rubber phase was dispersed in the continuous PP matrix, and that most aluminium hydroxide particles were uniformly distributed in the rubbery phase, and that much finer rubbery domains were found in the PP/Zn-S-EPDM/aluminium hydroxide composites. 28 refs.

The performance advantages of protective composite materials based on chlorosulphonated polyethylene (CSPE) are described. However, problems with the application of such coatings are reported to exist due to curing at high temperatures, their high viscosity, and low adhesion. To overcome this and to be able to create fire-proofing coatings with increased strength and adhesion properties which can be cured at normal temperatures, a study was made of the processes of structure formation of CSPE. This paper reports on the influence on the physicomechanical properties of composites based on CSPE in terms of the nature and concentration of the curing agent and the cure temperature, and also the influence on their properties of chemical modification. To study the processes of structure formation of CSPE, alkoxy and hydroxy organometallic compounds were used in the investigation. The parameters of the three-dimensional structure of the CSPE were determined from data of equilibrium swelling of specimens in toluene. To increase the strength characteristics of CSPE, use was made of an epoxy-containing modifier. Results of tests indicated that the use of an epoxy-containing oligomer as the modifier led to an increase in the adhesion of composites to the metallic substrate. Protective coatings made on the basis of modified CSPE were characterised by heat ageing resistance, high strength and elasticity, UV resistance and high cracking resistance. 4 refs. (Article translated from Plasticheskie Massy, No.8, 2004, p.31-2)