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排序方式: 共有827条查询结果,搜索用时 78 毫秒
1.
2.
Bisphenol A polycarbonate is shown to be miscible with a vinylidene chloride based polymer containing 13.5% by weight of vinyl chloride. On the other hand, polycarbonate is found to be immiscible with poly(vinyl chloride), poly(vinylidene fluoride), and polyepichlorohydrin. 相似文献
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5.
Stuart M. Barlow Anthony P. Bimbo Eric L. Miller Snorri Thorisson D. E. Walters 《Journal of the American Oil Chemists' Society》1997,74(9):1077-1083
Twenty-two laboratories participated in a collaborative test to determine the iodine value (IV) of eight samples of fish oil
(four with IV<150, four with IV>150) with either carbon tetrachloride (AOCS Official Method Cd 1–25) or cyclohexane (AOCS
Recommended Practice Cd 1b-87) as solvent and either 1 or 2 h of reaction time. Laboratories received coded duplicate samples
(hidden duplicates) and carried out duplicate determinations on each oil by each solvent-time combination (open duplicates).
Replacing carbon tetrachloride with cyclohexane resulted in a lower IV (P<0.001). The decrease averaged 1.6 IV units for low-IV oils and 3.8 IV units for high-IV oils; this difference in response
of 2.2 IV units between low- and high-IV oils was significant (P<0.001). Increasing the reaction time had a relatively small effect (0.34±0.18). There was no interaction of reaction time
with solvent or oil type. Cyclohexane caused emulsions, which made it difficult to titrate residual iodine and thus increased
the variability of the determination. The repeatability standard deviations (s
r
), based on hidden duplicates, for 1-h reaction time with carbon tetrachloride and cyclohexane were 2.17 and 3.35, respectively.
The corresponding reproducibility standard deviations were 2.73 and 4.53. 相似文献
6.
Blends of polycarbonate and the copolyester based on 1,4-cyclohexanedimethanol and a mixture of terephthalic and isophthalic acids are known to be completely miscible. This study was concerned with various chemical events which may occur in this system, particularly during melt processing. Degradation reactions were studied by both TGA and dilute viscometry techniques, and some indications of component interaction were noted. The residual titanium catalyst from the copolyester formation was found to produce color formation by interaction with phenolic end groups in the polycarbonate and to promote interchange reactions. Both events could be suppressed by deactivation of the residual catalyst with appropriate additives. An indication of the extent of interchange reactions was obtained by following the crystallizability of the copolyester component using differential scanning calorimetry. 相似文献
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J. W. Barlow 《Polymer Engineering and Science》1978,18(3):238-245
The volume of cis-1,4-polybutadiene between 5 and 55°C and 1 and 3000 atmospheres was measured to within a relative error of 0.1 percent with an especially developed, bellows-type dilatometer. The presence of a small transition near 55°C was indicated by analysis of the data and confirmed by differential thermal analysis. 相似文献
9.
Phase behavior of blends of aliphatic polyesters with a vinylidene chloride/vinyl chloride copolymer
A series of aliphatic polyesters having CH2/COO ratios from 2 to 14 in their repeat units were blended with a copolymer of vinylidene chloride containing 13.5% by weight of vinyl chloride. Blends of polyesters having CH2/COO < 4 did not form completely miscible amorphous phases, whereas polyesters having CH2/COO ≥ 4 did form completely homogeneous amorphous phases for all temperatures below the decomposition point except for the polyester with CH2/COO = 14 which showed reversible phase separation on heating, i.e., lower critical solution temperature behavior. Interaction parameters were estimated by melting point depression and by analog calorimetry. The behavior reported here is qualitatively similar to that reported earlier for blends of aliphatic polyesters with poly(vinyl chloride), polyepichlorohydrin, polycarbonate, styrene–allyl alcohol copolymers, and the hydroxy ether of bisphenol A. 相似文献
10.
Polycarbonate blends with the linear aliphatic polyesters poly(ethylene succinate) (PES), poly(ethylene adipate) (PEA), poly(1,4-butylene adipate) (PBA), and poly(hexamethylene sebacate) (PHS) were prepared by solution casting. Blends containing PES, PEA, and PBA exhibited a single Tg by DSC and thus form a single, miscible amorphous phase with polycarbonate. However, blends containing PHS exhibited only partial miscibility. Crystallinity of the polyesters was reduced by mixing with polycarbonate; however, plasticization by the polyesters induced crystallization of the polycarbonate. Miscibility in these systems is the result of an exothermic heat of mixing stemming from an interaction of the carbonyl dipole of the ester group with the aromatic carbonate. The effect of polyester structure on miscibility with polycarbonate is interpreted by and correlated with heats of mixing obtained by direct calorimetry of low molecular weight liquid analogs of the polymers. 相似文献