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91.
将SEBS-g-MAH、PP-g-MAH、SBS、偶联剂、碳酸钙及其他助剂共混,用双螺杆挤出机挤出造粒,然后经注塑制成弹性体复合材料。SEBS-g-MAH的FTIR表明,MAH已被接枝到SEBS上;弹性体复合材料的FTIR表明,该复合材料具有其主要组分的特征吸收峰;DSC分析表明,弹性体复合材料在142.8℃出现了一个熔融峰,说明弹性体复合材料中各组分很好地融为一体,没有出现相分离现象;SEM表明,弹性体复合材料形成"海-岛"结构,赋予弹性体复合材料很好的韧性。 相似文献
92.
Jeung Hee Lee Casimir C. Akoh Ki-Teak Lee 《Journal of the American Oil Chemists' Society》2008,85(1):1-11
Lipase-catalyzed interesterified solid fat was produced with fully hydrogenated soybean oil (FHSBO), and rapeseed oil (RSO)
and palm stearin (PS) in a weight ratio of 15:20:65, 15:40:45 and 15:50:35. The interesterified fats contained palmitic (27.8–44.6%),
stearic (15.6–16.2%), oleic (27.5–36.5%) and linoleic acids (8.0–13.5%). After interesterification of the blends, the physical
properties of the products changed and showed lower melting points and solid fat contents, different melting and crystallization
behaviors as well as the formation of more stable crystals. The produced interesterified fats (FHSBO:RSO:PS 15:20:65, 15:40:45
and 15:50:35 blends) contained desirable crystal polymorphism (β′ form) as determined by X-ray diffraction spectroscopy, a
long plastic range with solid fat content of 51–63% at 10 °C to 4–12% at 40 °C, and melting points of 39 (15:50:35), 42 (15:50:45)
and 45 °C (15:20:65). However, a reduction in tocopherols (α and γ) content and a reduced oxidative stability were observed
in the interesterified fats. The physical properties of the interesterifed fats were influenced by the amount of PS, resulting
in more hardness and higher solid fat contents for 15:20:65 than 15:40:45 and 15:50:35 blends. The present study suggested
that the produced interesterified fats containing trans-free fatty acids could be used as alternatives to hydrogenated types of bakery shortenings. 相似文献
93.
以玉米淀粉和丙烯酸为主要原料,采用溶液聚合的方法,制备了淀粉与丙烯酸接枝共聚物,用FTIR等方法对共聚产物结构进行了表征。研究了在过硫酸钾-硫代硫酸钠组成的氧化-还原引发体系中,引发剂、交联剂不同浓度及丙烯酸不同中和度等因素对共聚产物吸水性能的影响。实验结果表明采用K2S2O8-Na2S2O3引发体系,通过控制引发剂、交联剂浓度,接枝产物吸去离子水可达920 g/g;采用玉米粉代替玉米淀粉与丙烯酸接枝共聚,产物吸去离子水可达870 g/g;这些实验结果进一步提高了吸水树脂的吸水能力。 相似文献
94.
95.
The synthesis of graft copolymers by the grafting “onto” process in the molten state was described. Functional oligomers obtained by telomerization or by ATRP were reacted onto maleic anhydride grafted polypropylene (PP-g-MAH) and poly(ethylene-ter-maleic anhydride-ter-methyl acrylate) (P(E-ter-MAH-ter-MeA)) to obtain PP-g-PMMA and P(E-ter-MAH-ter-MeA)-g-PMMA graft copolymers, respectively. The grafting of different mono-functional oligomers bearing hydroxyl, aliphatic amine or aromatic amine functions was investigated at 180 °C and at 200 °C. The grafting efficiency was very low in the case of hydroxyl-terminated PMMA, while the amine-terminated PMMA led to high yields. In the last part, PP-g-PMMA and P(E-ter-MAH-ter-MeA)-g-PMMA graft copolymers were synthesized by the reaction of aliphatic amine functional PMMA oligomers onto PP-g-MAH and P(E-ter-MAH-ter-MeA), respectively. The influence of the molecular weight of PMMA oligomers was investigated and showed that he grafting efficiency slightly decreases with the increasing molecular weight. However, this process allows the synthesis of PP-g-PMMA graft copolymers containing 6-45 wt% of PMMA side chains. The microstructure of the nanostructured PP-g-PMMA and P(E-ter-MAH-ter-MeA)-g-PMMA graft copolymers was investigated by TEM and SEM. This was established that the addition of PP-g-PMMA in PP/PMMA binary blends allows to control their morphologies and stabilities. 相似文献
96.
97.
98.
Cation-exchange adsorbents were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP)
fabric and polyethylene (PE) hollow fiber and subsequent phosphonation of epoxy groups of poly(GMA) graft chains. The adsorption
characteristics of Pb2+, Cu2+ and Co2+ for the two cation-exchange adsorbents were studied. In the grafting of GMA onto PP fabric, the degree of grafting (%) increased
with an increase in reaction time, reaction temperature, and pre-irradiation dose. The maximum grafting yield was observed
around 60% GMA concentration. In 50, 130 and 250% GMA-grafted PP fabric, the content of phosphoric acid was 1.52, 3.40 and
4.50 mmol/g at 80 °C in the 85 % phosphoric acid aqueous solution for 24 h, respectively. The adsorption of Pb2+, Cu2+ and Co2+ by PP fabric adsorbent was enhanced with an increased phosphoric acid content The order of adsorption capacity of the PP
fabric adsorbent was Pb2+>Co2+>Cu2+. In adsorption of Pb2+, Cu2+ and Co2+ by PE hollow fiber, the amount of Pb2+ adsorbed by the PE hollow fiber adsorbent containing 1.21 mmol/g of -PO3H wasca. 54.4 g per kg. The adsorption amount of Cu2+ and Co2+ in the same PE hollow fiber wasca. 21.0 g per kg andca. 32.1 g per kg, respectively. The order of adsorption of the PE hollow fiber adsorbent was Pb2+>Co2+>Cu2+. 相似文献
99.
Jieh-Ming Huang Ming-Yih Ju Peter P. Chu Feng-Chih Chang 《Journal of Polymer Research》1999,6(4):259-266
The crystallization and melting behaviors of poly(trimethylene terephthalate) (PTT) have been studied by differential scanning
calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and solid-state NMR. At certain crystallization temperatures (Tc) for a given time, the isothermally crystallized PTT exhibits two melting endotherms, which is similar to that of PET and
PBT. At higher crystallization temperature (Tc = 210 °C), the low-temperature endotherm is related to the melting of the original crystals, while the high-temperature endotherm
is associated with the melting of crystals recrystallized during the heating. The peak temperatures of these double-melting
endotherms depend on crystallization temperature, crystallization time, and cooling rate from the melt as well as the subsequent
heating rate. At a low cooling rate (0.2 °C/min) or a high heating rate (40 °C/min), these two endotherms tend to coalesce
into a single endotherm, which is considered as complete melting without reorganization. WAXD results confirm that only one
crystal structure exists in the PTT sample regardless of the crystallization conditions even with the appearance of double
melting endotherms. The results of NMR reveal that the annealing treatment increases proton spin lattice relaxation time in
the rotation frame, T1ρ
H, of the PTT. This phenomenon suggests that the mobility of the PTT molecules decreases after the annealing process. The equilibrium
melting temperature (T
m
o
) determined by the Hoffman-Weeks plot is 248 °C. 相似文献
100.
Melting behavior of a series of polyether-polyester block copolymers with low ether contents was studied. Significant melting-reorganization-remelting was suggested by means of differential scanning calorimetry. The equilibrium melting temperature of the copolymers was obtained by using the Hoffman-Weeks extrapolation. It has been found that the use of the on-set melting temperature for the Hoffman-Weeks plots is less reliable than the use of the corrected peak melting temperature. Copolymerization of polyetheramides with polyesters leads to a significant melting temperature suppression for the polyester crystal. We hypothesize that the locations of the junction points between blocks can be treated as chain ends for the crystallizable polyester blocks: the polyether-polyesters grow to form extended chain-like crystals with lamellar thickness limited by the polyester block length. For comparison, the nonlinear Hoffman-Weeks treatment, recently proposed by Marand, has also been applied to examine the behavior of melting temperature depression. Although the T m o obtained from nonlinear extrapolation is much higher than the T m o obtained from the Hoffman-Weeks extrapolation, similar trend regarding the composition dependence of T m o have been found. 相似文献