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徐卫兵, W. Xu, *, M. Ge and W.-P. Pan
Journal of Thermal Analysis and Calorimetry, Vol. 78 (2004),-0001,():
-1年11月30日
Polyvinyl chloride (PVC)/organic-montmorillonite composites were prepared by melt intercalation. Their structures and properties were investigated with X-ray diffraction (XRD), differential scanning calorimetry (DSC) and mechanical testing. The results showed that PVC chains could be intercalated into the gallery of organically modified montmorillonite to form exfoliated PVC/organic-montmorillonite nanocomposites, and the glass transition temperatures of PVC/organic-montmorillonite composites were lower than that of neat PVC. However, the tensile strength, and both the Izod type and Charpy notched impact strengths of PVC/organic-montmorillonite nanocomposites were fitted with the linear expressions: τ=535.07-6.39Tg, σI=378.76-4.59Tg and σC=276.29-3.59Tg, respectively
DSC,, glass transition temperature,, melt intercalation,, montmorillonite,, nanocomposite,, polyvinyl chloride
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【期刊论文】PP-g-MAH蒙脱土纳米复合材料的制备和性能*
徐卫兵, 梁国栋
高分子材料科学与工程,2003,19(6):123~125,-0001,():
-1年11月30日
采用熔融插层法成功制备了接枝物(PP-g-MAH)/有机蒙脱土(Org-MMT) 纳米复合材料, 用X射线衍射法检测了复合材料的层间距、微晶尺寸和晶胞参数的变化, 并考察了纳米复合材料的力学性能。结果发现, 对于PP-g-MAH/O rg-MMT=100∶20的复合材料, 接枝物大分子链难以插层进入有机蒙脱土片层间。增大PP-g-MAH/Org2MMT比例, 接枝物大分子链能插层进入有机蒙脱土片层, 形成插层型纳米复合材料。PP-g-MAH/Org-MMT=100∶10时, PP-g-MAH/Org-MMT复合材料110、040、041等晶面垂直于反射方向的微晶尺寸出现最小值, 且可获得较好的力学性能, 说明选择适当的接枝物/有机蒙脱土比例可降低聚丙烯的微晶尺寸, 改善力学性能, 但对复合材料晶胞参数的影响较小。
聚丙烯, 蒙脱土, 纳米复合材料, 层间距, 微晶尺寸, 晶胞参数
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徐卫兵, Weibing Xu, , Guodong Liang, Wei Wang, Shupei Tang, Pingsheng He, Wei-Ping Pan
,-0001,():
-1年11月30日
The nonisothermal crystallization kinetics of poly(propylene) (PP), PP-organic-montmorillonite (Org-MMT) composite, and PP-PP-grafted maleic anhydride (PPg-MAH)-Org-MMT nanocomposites were investigated by differential scanning calorimetry (DSC) at various cooling rates. Avrami analysis modified by Jeziorny and a method developed by Mo well-described the nonisothermal crystallization process of these samples. The difference in the exponent n between PP and composite (either PP-Org-MMT or PP-PP-g-MAH-Org-MMT) indicated that nonisothermal kinetic crystallization corresponded to tridimensional growth with heterogeneous nucleation. The values of halftime, Zc; and F(T) showed that the crystallization rate increased with the increasing of cooling rates for PP and composites, but the crystallization rate of composites was faster than that of PP at a given cooling rate. The method developed by Ozawa can also be applied to describe the nonisothermal crystallization process of PP, but did not describe that of composites. Moreover, the method proposed by Kissinger was used to evaluate the activation energy of the mentioned samples. The results showed that the activation energy of PP-Org-MMT was much greater than that of PP, but the activation energy of PP-PP-g-MAH-Org-MMT was close to that of pure PP. Overall, the results indicate that the addition of Org-MMT and PP-g-MAH may accelerate the overall nonisothermal crystallization process of PP.
poly(, propylene), (, PP), , nanocomposites, crystallization, kinetics (, polym., ),
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【期刊论文】环氧树脂/桐油酸酐/蒙脱土纳米复合材料固化动力学
徐卫兵, 沈时骏a, 鲍素萍a, 翟红波a, 徐卫兵a, b
应用化学,2004,21(2):130~431,-0001,():
-1年11月30日
用自制的有机蒙脱土,采用浇模固化成型法制备了环氧树脂/桐油酸酐/蒙脱土纳米复合材料。用DSC跟踪环氧树脂固化行为,用XRD分析有机蒙脱土的层间距变化,确定产物为部分剥离型的纳米复合材料。用Flynn-Wall-Ozawa、Kissinger及Crane方法对树脂进行动态测试分析,发现有机蒙脱土对体系固化有促进作用,使反应更易进行;并求解出活化能和反应级数等动力学参数。
环氧树脂,, 固化反应,, 动力学,, DSC
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徐卫兵, Xu Weibing a, b, He Pingsheng a, *, Chen Dazhu a
W.B. Xu et al./European Polymer Journal 39(2003)617-625,-0001,():
-1年11月30日
at lower temperature (<90℃) and decreases to 2 as the temperature increases. The addition of Org-MMT has no obvious effect on the apparent activation energy of the cure reaction. There is no special curing process required for the formation of an epoxy resin/Org-MMT/imidazole intercalated nanocomposite.
Epoxy resin, Montmorillonite, Nanocomposite, Cure, Gel time, Avrami equation
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