固相法氯化等规聚丙烯的制备

探讨了等规聚丙烯原料性质对氯化反应的影响,同时研究了氯化反应的基本特征。结果表明,原料等规聚丙烯的熔融指数高、粒度小,有利于进行氯化反应。氯化反应速率随着氯化程度的加深逐渐下降,反应温度和反应程度都会影响氯化氢的脱除。采用搅拌式固相法,控制适当的反应条件可以制得氯化度高于６０％的ＣＩＰＰ产品。     

氯化等规聚丙烯

1 前言自从1955年G·Natta首先开发等规聚丙烯以来,由于其原料来源丰富,价格低廉、具有高的结晶性、高熔点及高的立构规整性而获得了广泛的应用。目前聚丙烯已发展成为仅次于聚氯乙烯和聚乙烯而居世界第三位的塑料品种。随着聚丙烯生产和应用的发展,它的     

固相氯化法氯化等规聚丙烯结构分析

借助ＤＳＣ,ＩＲ,＾１Ｈ－ＮＭＲ方法对搅拌式固相氯化制备的氯化等规聚丙烯的宏观氯原子分布和微观氯原子分布进行了分析。结果表明,搅拌式固相氯化法能够迅速破坏等规聚丙烯的结晶,从而得到宏观氯原子分布均匀的ＣＩＰＰ。此方法制备的ＣＩＰＰ主要为等丙烯分子链上的仲氢原子被取代的产物。     

固相法化学降解等规聚丙烯

在剪切力作用和较低温度下,利用过氧化物对等规聚丙烯（PP）化学降解,得到了具有超高熔体流动速率（MFR）的PP降解产品。考察了降解时间对降解产品的MFR及相对分子质量的影响,发现随着降解时间的增加,MFR提高幅度逐渐减小,相对分子质量下降。用红外光谱和差示扫描量热法表征发现,降解PP出现了羰基和碳碳双键吸收峰．且羰基吸收峰随降解时间的增加而增强;PP降解产品在不同温度下的结晶结构未改变。     

固相法氯化等规聚丙烯的溶液性能

研究了固相法CIPP的稀溶液和浓溶液性能 ,结果表明 ,随着氯含量的增加CIPP稀溶液的特性粘数和浓溶液的粘度都呈下降趋势。溶液粘度随氯化反应温度的升高上升较快 ,在力化学降解下CIPP的溶液粘度下降较快。CIPP固含量超过 2 0 % ,粘度上升较快     

水相法合成氯化等规聚丙烯的研究

采用水相法合成氯化等规聚丙烯(CIPP)．研究了反应速度及溶解性能的影响因素。介绍了水相法CIPP的性能及其在油墨上的应用。     

氯化改性等规聚丙烯树脂合成的研究

采用溶液氯化方法,对固相接枝制得的等规聚丙烯接枝马来酸酐共聚物（IPP－g-MA）进行氯化反应,制得氯含量为30％－55％的氯化改性等规聚丙烯（MCPP）。用FT－IR、X光衍射、DSC和^13C NMR表征了产物的结构。MCPP树脂配制的聚丙烯塑料涂料和金属防腐蚀涂料均有很好的性能。     

二步光氯化悬浮法制备高氯含量的氯化等规聚丙烯

采用二步光氯化悬浮法制备了高氯含量的 CIPP,研究了氯化温度、通氯量、固液比以及光照时间和方式等对 CIPP含氯量的影响。制备了含氯量在 61 %～ 63 %的高氯 CIPP,筛选出滤波介质并解决了光氯化法生产高聚物时灯易结膜的技术难点。得出的最佳工艺条件是 :在第一阶段 m( PP)∶ m(氯苯 ) =1∶ ( 8.5～ 9) ,反应温度 ( 1 1 0± 2 )℃ ,光照 5h,通氯速率为 4 0 cm3/min;第二阶段 m ( CPP)∶ m ( CCl4 )∶ m ( H2 O) =1∶ 3∶ 1 0 ,反应温度 70～ 75℃ ,光照反应时间 6～ 8h,通氯速率为 4 0cm3/min。     

等规聚丙烯的深度氯化及其在涂料中的应用

采用溶液催化氯化工艺对等规聚丙烯（IPP）进行深度氯化,制得氯含量达52％～62％的氯化等规聚丙烯（CIPP）。该氯化等规聚丙烯可代替过氯乙烯、氯化橡胶用于各种防腐涂料,所得防腐蚀涂料具有良好的性能。     

无溶剂光氯化悬浮法制备低氯化度的氯化等规聚丙烯

用无溶剂光氯化悬浮法进行等规聚丙烯 (IPP)氯化反应 ,考察了反应时间、引发剂、通氯量、悬浮剂和金属盐等因素对氯化速度的影响 ,以偶氮二异丁腈为引发剂 ,m(IPP)∶m(H2 O) =1∶1 5,通氯量为 40mL min ,反应时间 1 0h ,可得到氯质量分数在 2 5%左右的氯化聚丙烯。金属离子可明显缩短其诱导期 ,但反应后期 ,金属离子的存在对氯化反应起抑制作用。     

固相氯化法用隔离剂的评价

通过研究隔离剂对氯化反应过程中烧结和粘结的影响,评价了多种隔离剂对气－ 固相氯化反应的作用,为隔离剂的选择提供了依据。研究结果表明,能够有效地减轻烧结现象的最佳隔离剂用量为４ ％ ,利用两种白炭黑的协同作用复配而得的隔离剂体系可以有效地减轻粘结现象。     

温度控制方式对气—固相氯化反应的影响

采用搅拌式固相法制备氯化等规聚丙烯（CIPP）,讨论了不同的温度控制方式对等规聚丙烯氯化反应的影响。结果表明,在恒定的温度条件下,100～103℃是较好的反应温度,温度过低产物的氯分布不均匀,温度过高容易发生脱氯化氢现象。在热处理方式下,由于气-固相反应特有的烧结和粘结影响严重,不利于氯化反应的进行。逐步长温的控温方式是制备CIPP的最佳温度控制方式。     

Porous SiC ceramics prepared via freeze-casting and solid state sintering

Porous SiC ceramics were prepared by freeze-casting process. In order to enhance the mechanical properties of the porous SiC, poly(vinyl alcohol) (PVA) was added as binder and pore morphology controller in this work. The results indicated that high porosity (>60%) SiC ceramics was obtained although the sintering temperature was over 2000 °C. The pore structure could be divided into two kinds: macropores generated by sublimation of large ice crystals, and micropores in the ceramic matrix caused by sublimating of small ice crystals, stacking of SiC particles, and burning out of PVA. With the increase of the sintering temperature, the specimens exhibited higher density, thus resulted in higher strength. Porous SiC ceramics sintered at 2100 °C showed a good flexural strength of 11.25 MPa with an open porosity as high as 66.46%.     

The effect of silica on the crystallization of isotactic poly(propylene oxide)

The addition of one part, by weight, of fine particle silica to one hundred parts isotactic poly(propylene oxide) causes a retardation in the rate of radial growth of spherulites at all temperatures between 268 and 313 K. The results have been fitted empirically by use of the Hoffman-Lauritzen equation suitably modified to account for effects due to the presence of the silica. At certain temperatures the presence of the silica also causes a change in the morphology of the spherulites.     

Crystallization behavior of low molecular mass isotactic poly(propylene) fractions

Summary The overall crystallization and linear crystal growth kinetics for the (monoclinic) -form of low molecular mass isotactic poly(propylene) (i-PP) fractions have been studied. Two processes can be found for the overall crystallization study via differential scanning calorimetry (DSC). Based on the nucleation theory, both the half-life time of the first process in overall crystallization kinetics and the linear crystal growth data show two regime transitions, namely, regime I/II and II/III transitions.     

氯化聚丙烯溶度参数的研究

氯化聚丙烯是对聚丙烯材料有很好的粘结力 ,为了进行基础的应用研究 ,用浊度法对其溶度参数进行了测定 ,得到其溶度参数为 16 .72～ 2 1.15 (J/cm3 ) 1/ 2 。氯化聚丙烯溶解性能实验表明 :氯化聚丙烯属于弱极性物质。在溶度参数接近时 ,一般弱极性溶剂为良溶剂 ,中等极性溶剂为微溶溶剂。还用三维溶度参数对CPP的溶解性能进行了讨论。     

How do chlorinated poly(olefins) promote adhesion of coatings to poly(propylene)?

The mechanism by which chlorinated poly(olefin) (CPO) primer coatings promote adhesion of paints to poly(propylene) and thermoplastic poly(olefins) (TPO) has been examined by surface characterization techniques including electron spectroscopy for chemical analysis (ESCA), time-of-flight secondary ion mass spectrometry (ToFSIMS) and transmission electron microscopy (TEM). The coatings, their interfacial failures, and taper-cut cross sections were studied, using both waterborne and solventborne CPO primers. The results were then correlated with peel strength and crosshatch adhesion tests. CPO primers do not penetrate deeply into the poly(olefin) substrates, but are quite mobile following application of the topcoat. Solventborne CPO's generally showed adhesive failure at the CPO/poly(olefin) interface when dried at ambient temperatures. Test results are also reported for waterborne CPO adhesion promoters.     

Dielectric,mechanical and thermal properties of some chlorinated poly (p-phenylene oxide)s in the solid state

The dielectric, mechanical and thermal properties were investigated for poly(2,6-dichloro-1,4-phenylene oxide) (PDCPO), poly(2-chloro-6-methyl-1,4-phenylene oxide) (PCMPO) and poly(2,6-dimethyl-1,4-phenylene oxide) (PDMPO). PDCPO exhibited two dielectric secondary relaxations designated as β and γ processes around 160 and 100K, respectively. The γ process was assigned to the motion of a trace of chloroform included in the PDCPO film. A blend film PDMPO/PCMPO ($\text{9}\text{1}$ mixing ratio) exhibited dielectric relaxation around 330K and the process was assigned to the rotation of phenyl group with respect to oxygen-phenyl-oxygen axis. No dielectric relaxation was observed for the PDMPO film dried carefully, while the PDMPO film kept under an atmosphere of water vapour exhibited dielectric relaxation due to the motion of the water molecules at about 180K. Tensile stress at break measured on PDCPO prepared by Stamatoff's method was 38 MPa and was much higher than that for PDCPO prepared by the method reported by Blanchard et al. Temperature dependence of the dynamic Young's modulus for PDCPO measured at 110 Hz exhibited no appreciable loss peak in the range below 480K. Glass transition temperatures for PDCPO, PCMPO and PDMPO were determined to be 490, 445 and 500K, respectively, by differential scanning calorimetry.