Thermal analysis, poly

Thermal Analysis - Differential Scanning Calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to characterize the thermal properties of the polymers synthesized. DSC analysis was performed on a Perkin-Elmer Differential Scanning Calorimeter, Model 2C with a thermal analysis data station. Thermal gravimetric analysis (TGA) was carried out on a DuPont thermal gravimeter, Model 951. From the DSC and TGA plots of poly (N-pheny 1-3,4-dimethylene-... 

The physical properties of the acid- and ion-containing polymers are quite interesting. The storage moduli vs. temperature behavior (Figure 8) was determined by dynamic mechanical thermal analysis (DMTA) for the PS-PIBMA diblock precursor, the polystyrene diblock ionomer and the poly(styrene)-b-poly(isobutyl methacrylate-co-methacrylic acid) diblock. The last two samples were obtained by the KC>2 hydrolysis approach. It is important to note that these three curves are offset for clarity, i.e. the modulus of the precursor is not necessarily higher than the ionomer. In particular, one should note the same Tg of the polystyrene block before and after ionomer formation, and the extension of the rubbery plateau past 200°C. In contrast, flow occurred in... 

Poly(methyl 3-(l-oxypyridinyl)siloxane) was synthesized and shown to have catalytic activity in transacylation reactions of carboxylic and phosphoric acid derivatives. 3-(Methyldichlorosilyl)pyridine (1) was made by metallation of 3-bromopyridine with n-BuLi followed by reaction with excess MeSiCl3. 1 was hydrolyzed in aqueous ammonia to give hydroxyl terminated poly(methyl 3-pyridinylsiloxane) (2) which was end-blocked to polymer 3 with (Me3Si)2NH and Me3SiCl. Polymer 3 was N-oxidized with m-ClC6H4C03H to give 4. Species 1-4 were characterized by IR and H NMR spectra. MS of 1 and thermal analysis (DSC and TGA) of 2-4 are discussed. 3-(Trimethylsilyl)-pyridine 1-oxide (6), l,3-dimethyl-l,3-bis-3-(l-oxypyridinyl) disiloxane (7) and 4 were effective catalysts for conversion of benzoyl chloride to benzoic anhydride in CH2Cl2/aqueous NaHCC>3 suspensions and for hydrolysis of diphenyl phosphorochloridate in aqueous NaHCC>3. The latter had a ti/2 of less than 10 min at 23°C. 

We report here the results of our recent studies of poly(alkyl/arylphosphazenes) with particular emphasis on the following areas (1) the overall scope of, and recent improvements in, the condensation polymerization method (2) the characterization of a representative series of these polymers by dilute solution techniques (viscosity, membrane osmometry, light scattering, and size exclusion chromatography), thermal analysis (TGA and DSC), NMR spectroscopy, and X-ray diffraction (3) the preparation and preliminary thermolysis reactions of new, functionalized phosphoranimine monomers and (4) the mechanism of the polymerization reaction. 

All of the organohalogen compounds studied were commercial products obtained from various manufacturers and used as received. Only the DBDPO was purified further by recrystallization for some of the chromatography and thermal analysis experiments. Samples of antimony trioxide and antimony pentoxide were also obtained from commercial sources. The ultrapure antimony trioxide, bismuth trioxide, bismuth metal, antimony metal, dibenzofuran and diphenyl ether were all obtained from Aldrich Chemicals. The poly(propylene) (PP) resin was 0.7 mfi, food grade from Novamont and the poly(ethylene) was unstabilized, high molecular weight, HDPE from American Hoechst. 

Recently, Kroeze et al. prepared polymeric iniferter 34 including poly(BD) segments in the main chain [152]. They successfully synthesized poly(BD)-block-poly(SAN), which was characterized by gel permeation chromatography, elemental analysis, thermogravimetric analysis, NMR, dynamic mechanical thermal analysis, and transmission electron microscopy. By varying the polymerization time and iniferter concentration, the composition and the sequence length were controlled. The analysis confirmed the chain microphase separation in the multiblock copolymers. 

Sealants obtained by curing polysulfide liquid polymers with aryl bis(nitrile oxides) possess stmctural feature of thiohydroximic acid ester. These materials exhibit poor thermal stability when heated at 60°C they soften within days and liquefy in 3 weeks. Products obtained with excess nitrile oxide degrade faster than those produced with equimolar amounts of reagents. Spectroscopic studies demonstrate that, after an initial rapid addition between nitrile oxide and thiol, a second slower reaction occurs which consumes additional nitrile oxide. Thiohydroximic acid derivatives have been shown to react with nitrile oxides at ambient temperature to form 1,2,4-oxadiazole 4-oxides and alkyl thiol. In the case of a polysulfide sealant, the rupture of a C-S bond to form the thiol involves cleavage of the polymer backbone. Continuation of the process leads to degradation of the sealant. These observations have been supported by thermal analysis studies on the poly sulfide sealants and model polymers (511). 

Thermal Analysis. Ito et al. have reported the effect of ester structure on ease of thermolysis and Aal-1 acidolysis of poly(p-vinylbenzoates) (//) and... 

Fig Differential thermal analysis curve for amorphous poly (ethylene terephthalate). 

Figure shows the Differential thermal analysis curve for poly (ethylene terephthalate). The lower crystalline melting range in the specimen of figure below can be attributed to impurities present in the polymer. 

Cheng, Y.-Y., Brillhart, M., Cebe, P. and Capel, M., X-ray scattering and thermal analysis study of the effects of molecular weight on phase structure in blends of polybutylene terephthalate with polycarbonate, J. Poly. Sci., Polym. Phys., 34, 2953-2965 (1996). 

Thirdly, PMMI starts thermally degrading at about 154 C to form an anhydride [65,74]. Thermal analysis showed that the onset temperatures for degradation of the complexes PMMI/PDMA, PMMI/PEOX and PEMl/PVPo was substantially higher than those of the corresponding poly(monoalkyl itaconates), and the difference was attributed to the fact that hydrogen bonds in the complexes need to be broken before anhydride formation takes place. 

Vamell, D. F., Runt, J. P., Coleman, M. M. FT-IR and Thermal Analysis Studies of Blends of Poly(Caprolactone) and Homo- and Copolymers of Poly(vinylidene chloride). Preprint submitted to CARBON... 

Wilkes and coworkers studied polyrotaxanes derived from self-assembly of a polyurethane bearing paraquat moieties and BPP34C10 [130b]. The polyurethanes contained soft (poly(tetramethylene oxide)) and hard (paraquat ionene) segments. Interestingly, dynamic mechanical analysis indicated that polyrotaxanes had higher rubbery plateau moduli than the corresponding backbones. Thermal analysis revealed that the stability was enhanced by the formation of the polyrotaxanes. 

This hypothesis has been confirmed by the greatly improved thermal stability of PVC as a result of the formation of a graft copolymer of d -l,4-polybutadiene onto poly (vinyl chloride). The improved thermal stability is demonstrated by the almost total absence of discoloration on molding the graft copolymer into a film at 200°C in air, the reduced rate of dehydrochlorination on heating in an inert atmosphere at 180°C, and higher onset and peak temperatures for hydrogen chloride evolution as determined by differential thermal analysis. 

Thermal analysis (TGA) data of these siliconated block copolymers revealed that they are thermally more stable than the reference materials, poly(tetrahydrofuran block urethane) and poly(ethyleneglycol block urethane) copolymers. The thermal stability was found to depend on the silicone content, with stability increasing as the silicone content in the structure increases. 

Holland, B. J. and Hay, J. N. The kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopy. Polymer 2001 42 4825. 

DobkowskiZ, ZieleckaM (2002) Thermal analysis of the poly(siloxane)-poly(tetra-fluoroethylene) coating system. J Therm Analy Calorim 68(1) 147—158... 

Kyoumen, M. Baba, Y. Kagemoto, A., "Determination of Consolute Temperature of Poly[Styrene-ran- (Butyl Methacrylate)] Solutions by Simultaneous Measurement of Differential Thermal Analysis and Laser Transmittance," Macromolecules, 23, 1085 (1990). 

Fig. 15. DiiTerential thermal analysis traces of a blend of chlorinated polyethylene with poly(methyl methacrylate) obtained by heating at a rate of 10 °C/min. The blend was kept at the quoted temperatures for 10 min. and was quenched prior to scanning. The appearance of two T s after treatment at 190 C is indicative of phase separation at this temperature...

Thermal analysis as well as particle morphology and redispersion of precrosslinked poly(organosiloxane) microparticles proved to be promising with regard to an application as potential toughening agents. This caused us to investigate the principal suitability of silicone particles as modifiers for thermoplastic polymers. 

The sensitivity of poly(methyl methacrylate), PMMA, to x-rays is enhanced by the addition of poly(epichlorohydrin). The two polymers are miscible as shown by thermal analysis and by optical clarity of blends. 

Morphological changes, which are classified into four groups, have been correlated to the degree of topotactic control. Thermal analysis has been studied on DSP poly-DSP in some detail. Two main endothermic peaks of as-polymerized poly-DSP crystals are characterized as thermal depolymerization in the crystalline state and crystal melting point followed by thermal depolymerization in the molten state. From the results of the studies on the heat treatment of as-polymerized polymer crystals, a reversible topochemical processe has been established. 

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