新型氯乙烯非均相聚合动力学和成粒机理

对以正丁烷（But)为反应介质的新型氯乙烯（VC）非均相聚合动力学和成粒机理进行了研究，根据VC-But二元体系气液平衡方程，由聚合过程气相压力或组成变化计算VC聚合转化率，VC非均相聚合的诱导期不明显，自动加速现象一般发生在聚合前、中期，后期聚合速率较小，新型VC非均相聚合PVC树脂的体粒径与悬浮PVC树脂相当，数均粒径较小，PVC颗粒由基本不熔结的初级粒子组成，颗粒内部初级粒子分布密度大，粒径大，孔隙率高；而在颗粒表层初级粒子分布密度高，粒径小，孔隙率低；树脂的增塑剂吸收率远大于悬浮PVC树脂，根据PVC树脂的颗粒特性和PVC与VC／But混合液的溶解度参数差异，推断聚合成粒机理为：PVC分子链在很低转化率时就从聚合介质中沉析出来并聚集形成微区，初级粒子和颗粒；后期成粒过程包括颗粒内部初级粒子的增长和向表层的离心聚集，颗粒对新形成的大分子链及其初级聚集体的捕捉等。     

ACR/纳米SiO2复合粒子的合成及其对PVC的增韧作用

研究了细乳液聚合制备ACR/纳米SiO2复合粒子及其对PVC的增韧作用。对丙烯酸酯单体中的纳米SiO2粒子进行偶联改性,提高了ACR对纳米粒子的包覆率和接枝率,复合粒子与PVC共混后纳米SiO2粒子在PVC基体中的分散性好。复合粒子对PVC的增韧效果明显优于纳米SiO2粒子和未改性ACR共聚物,复合粒子的用量较少时,就可明显提高PVC的冲击强度。     

PVC的微发泡处理及PVC/CaCO3的原位复合

研究了用原位生成法制备PVC/纳米CaCO3复合母粒的过程. 首先利用混合溶剂将PVC粉料溶胀,同时带入发泡剂偶氮二异丁腈,在112oC下进行固相微发泡. 利用已发泡的PVC,采用原位生成法制备了纳米CaCO3/PVC复合母粒. 通过扫描电镜观察,发现已发泡PVC颗粒表面布满微孔,纳米级CaCO3填充在PVC孔洞里. PVC/纳米CaCO3复合母粒同时起到了增韧增强的作用.     

有机高分子包覆的滑石粉在PVC加工中应用

表面偶联化处理的滑石粉微粒经乳液聚合甲基丙烯酸甲酯接枝共聚物包覆，构成复合粒子。通过红外光谱（FT—IR）、扫描电镜（SEM）等检测表征,确认其核壳聚合物包覆的形态结构，并用于填充聚氯乙烯（PVC）塑料。结果表明，与未经包覆的对照粒子填充PVC材料的性能相比，其填充的PVC拉伸强度、冲击强度得到了大幅提高，包覆的复合粒子可作为新颖的增强增韧改性剂用于PVC电缆料或其他制品中。     

改性TiO2在PVC基体中的分散行为研究

通过熔融共混法制备了聚氯乙烯/二氧化钛(PVC/TiO2)复合材料,通过扫描电镜观察TiO2粒子在PVC中的分散状态,并测定了材料的力学性能。结果表明,在粒径一定的条件下,TiO2粒子在PVC中的分散状态及复合材料的力学性能与表面改性方法密切相关;经过钛酸四丁酯偶联剂[Ti(OBu)4]、γ-氨丙基三乙氧基硅烷偶联剂（KH-550）、聚甲基丙烯酸甲酯（PMMA）改性的TiO2粒子能有效提高粒子在塑料中的分散性及冲击强度,当PMMA改性的TiO2粒子添加量为2.5份时,冲击强度提高超过100 %;而经十二烷基磺酸钠（SLS）改性的粒子团聚严重,复合材料力学性能明显下降。     

Small‐angle X‐ray scattering study of modified porous suspension–poly(vinyl chloride) particles

Small‐angle X‐ray scattering (SAXS) was applied to investigate the microstructure of unmodified and modified porous commercial suspension‐type poly(vinyl chloride) (PVC) particles. The modified PVC particles were prepared by an in situ stabilizer‐free polymerization/crosslinking of particles absorbed with a monomer/crosslinker/peroxide solution. The modifying polymers include styrene with or without divinyl benzene (DVB) as a crosslinker and methyl methacrylate (MMA) with or without ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The SAXS method was used to highlight the effect of polystyrene (PS) on the microstructure of PVC particles and to evaluate the characteristic lengths, both in the PVC/PS and the PVC/XPS (PS crosslinked with 0 and 5% DVB, respectively) systems. A model is suggested, where during the synthesis modification process, swelling of PVC by styrene and styrene polymerization occur simultaneously. PVC swelling by styrene causes destruction of the PVC subprimary particles, whereas styrene polymerization leads to phase separation resulting from incompatibility of the polymers. It was further suggested that because of PVC swelling by styrene, structure of the subprimary particles is lost. Therefore the characteristic lengths of PVC/PS and PVC/XPS, as calculated from the SAXS measurements, were attributed to the size of the phase‐separated PS and XPS inclusions, respectively. The SAXS method also shows that PMMA and XPMMA do not influence the PVC microstructure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1024–1031, 2005     

CPE对纳米CaCO3增韧PVC复合材料界面和性能的影响

研究了CaCO3/CPE(氯化聚乙烯)/PVC(聚氯乙烯)纳米复合材料的结构和性能,探讨了CPE对纳米CaCO3/PVC复合材料界面作用和力学性能的影响. SEM结果显示,引入CPE可明显改善纳米CaCO3颗粒在PVC基体中的分散性和相容性,提高其界面作用. 引入界面作用参数定量表征纳米CaCO3颗粒与基体之间的界面结合作用,证实随着CPE加入量的增大,基体和颗粒之间的界面作用逐渐增大. 力学性能研究表明,相对于仅用纳米CaCO3增韧PVC,在CPE加入量为PVC的0~8%(w)范围内,用CPE和纳米CaCO3协同增韧可以更好地提高复合材料的冲击强度. 复合材料的冲击强度在CaCO3/CPE/PVC质量比为25/8/100时达到纯PVC的5.6倍,是纳米CaCO3/PVC(25/100)体系的2倍.     

浓乳液双相聚合制备聚丙烯酸丁酯粒子及其对聚氯乙烯的改性研究

用浓乳液双相法合成PBA，通过在合成过程中添加不同用量的DVB交联剂和MMA硬单体调节PBA粒子的硬度及性能，研究了不同DVB及MMA加入量的PBA对PVC力学性能的影响。并通过复合材料断面微观形态分析验证了实验结果。结果表明：在BA单体中加入硬单体MMA和交联剂DVB均可提高PBA粒子的硬度，当MMA和DVB用量较大时，会导致粒子呈现刚性，不利于PBA对PVC改性；PBA粒子与硬质PVC共混后能较好地分散在PVC中，并能在提高材料冲击强度的同时，拉伸强度也有所改善；DVB和MMA的用量均为2mL时，PBA异形粒子对硬质PVC的改性效果最好。此配方PBA粒子与PVC相容性好、界面结合力强。     

纳米CaCO_3的接枝改性及其填充PVC复合材料的性能

采用表面原位接枝聚合在纳米CaCO3颗粒表面引入聚甲基丙烯酸甲酯(PMMA)或聚丙烯酸丁酯(PBA),用共混法制备了纳米CaC03/PVC复合材料,研究了不同界面特性时纳米CaCO,/PVC复合材料的力学性能.研究结果表明:通过表面原位接枝聚合反应可以在纳米CaCO3颗粒表面接枝PMMA和PBA;表面接枝聚合改性大大促进了纳米CaCO3粒子在PVC基体中的分散行为,增加了复合材料的拉伸强度以及与聚合物的界面粘接强度,但复合材料的冲击强度有所下降.     

可反应性纳米SiO_2对PVC颗粒结构、性能的影响

以VCM和可反应性纳米SiO2(RNS)为原料,采用原位聚合方法合成了PVC/RNS复合材料,考察了RNS对PVC树脂颗粒结构和性能的影响,并利用FTIR和XPS等分析了RNS与PVC之间的相互作用机制。结果表明:①PVC/RNS颗粒内部结构较为疏松多孔,可见较多的初级粒子;②与PVC树脂相比,PVC/RNS复合材料的黏数略有增加,增塑剂吸收量提高,表观密度略有降低,颗粒粒度分布变化不大,维卡软化温度小幅增加,热降解速率降低;③RNS与部分PVC分子链之间形成了强化学键结合。     

PVC dust removal from the air by a new dynamical scrubber

Removal of the poly vinyl chloride (PVC) dust particles by a new dynamical scrubber in a PVC manufacturing plant is presented in this work. The effects of inlet air flow rate (containing PVC particles) and water flow rate (the physical absorber of particles) on the PVC dust removal efficiency were investigated. The size of the PVC particles which have been treated in this study was ranging from 0.5 up to 20 μm. The experimental results showed approximately 100% removal efficiency for particles larger than 1 μm and 73% for 0.5 μm particles while employing low water flow rates. The results of these experimental tests indicate a good performance of the scrubber in a short residence time (about 2 s) which is also completely economic for removing fine particles.     

Particle features of poly(vinyl chloride) resins prepared by a new heterogeneous polymerization process

The heterogeneous polymerization of vinyl chloride monomer (VCM), with n‐butane as the reaction medium, was used to prepare poly(vinyl chloride) (PVC) resins. The particle features of the resulting resins and the particle formation mechanism of the polymerization process were investigated. The PVC resins prepared by the new polymerization process had a volume‐average particle size comparable to that of suspension PVC resins and a lower number‐average particle size. From scanning electron micrographs, it could be seen that the new PVC resins had a regular particle shape and a smooth surface with no obvious skin. They also had a high porosity. The new PVC resins were composed of individual and loosely aggregated primary particles. The diameter of the primary particles in the top layer of the grains was smaller than that of the primary particles in the center part of the grains. On the basis of the particle features of these PVC resins, a particle formation mechanism for the new polymerization process was proposed. PVC chains precipitate from a VCM/n‐butane mixed medium to form primary aggregates at a very low conversion, and the primary aggregates of the PVC chains aggregate to form primary particles, which further aggregate to form grains. The primary particles and grains grow by the capture of newly formed PVC chains and their primary aggregates and by polymerization occurring inside the aggregates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 954–958, 2003     

吸水膨胀型PVC基热塑性弹性体的制备及性能

以熔融共混法制备了吸水膨胀型PVC基热塑性弹性体,表征了PAAS粒子在基体中的分散行为及对复合体系力学性能的影响,并对其吸水膨胀性能进行了表征。结果表明:在PVC/DOP/PAAS复合体系中,PAAS呈均匀分散;随着PAAS含量的提高,复合体系的拉伸强度、撕裂强度、断裂伸长率、扯断伸长率趋于明显下降趋势,而硬度则趋于缓慢增加;在本研究范围内,PVC/DOP/PAAS复合体系均属于热塑性弹性体;当PAAS的加入量超过40份后,复合体系呈现出显著地吸水膨胀行为。     

Influences of chlorinated polyethylene and oxidized polyethylene on the fusion of rigid poly(vinyl chloride) compounds

Fusion time, fusion temperature, and fusion torque of poly(vinyl chloride) (PVC) compounds with various components were studied in this article. Influences of chlorinated polyethylene (CPE), oxidized polyethylene (OPE), and calcium stearate on fusion characteristics of PVC compounds were illustrated. The synergistic reaction among CPE, OPE, and calcium stearate forms a powerful and effective processing aid that allows the PVC particles to fuse more quickly and uniformly. In PVC/CPE compounds, a higher concentration of CPE can function like a processing aid and help PVC particles to fuse together easily. Meanwhile, the interaction between a higher concentration of OPE and calcium stearate in PVC/OPE compounds can promote the PVC particles to fuse together easily in the beginning of the fusion process. However, the external lubricant property of OPE still exists and results in more intact PVC microparticles not fused. The fusion temperature of the PVC in a Haake mixing bowl increases as the fusion time increases. On the other hand, the fusion torque decreases as the fusion time increases. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 699–705, 1999     

Processability,morphology, thermal,and mechanical properties of rigid PVC composites with liquid macromolecular modifier‐coated CaCO3

Rigid poly(vinyl chloride) (PVC)/CaCO₃ and PVC/liquid macromolecular modifier (LMM) coated CaCO₃ (PVC/LCC) composites were both fabricated by melt mixing. The processability, micro‐structure, dynamic mechanical behavior and mechanical properties of PVC/CaCO₃ and PVC/LCC composites were studied by using torque rheometer, scanning electron microscope (SEM), dynamic mechanical analysis (DMA), and universal mechanical testing machine. The results showed that the synergistic effect of LMM and CaCO₃ particles accelerated the plasticization of PVC resins. The processability of PVC/LCC composites was improved. The dispersion of LCC in PVC matrix was improved by the modification of CaCO₃ particles with LMM. The T_gs of PVC/LCC composites were enhanced by filling with LCC. Because of the synergistic toughening of LMM and CaCO₃ particles, the PVC/LCC composites exhibited excellent notched impact properties at the optimum value of LCC particles content. POLYM. COMPOS., 36:1286–1292, 2015. © 2014 Society of Plastics Engineers     

Effect of hydrophilization of surface of PVC particles on their water dispersion stability

The results of studies on the effect of oxyethylenated surfaces of PVC on the water dispersion stability of particles are presented. The hydrophilizating agent introduced into PVC particles was ethylene polyoxide glycol with molecular weights from 400 to 6000. Non-ionic surfactants such as oxyethylenated oleinic acid, oxyethylenated plant oil, oxyethylenated lauryl alcohol and oxyethylenated saturated aliphatic alcohol were used as stabilizers of PVC particles in water. It was found that the aqueous dispersions of PVC plastisol with the best stability were obtained when polyethylenoxide glycol with molecular weight of 6000 was applied as hydrophilizating agent and oxyethylenated oleic acid or oxyethylenated saturated aliphatic alcohol as stabilizer. In these cases, stability is highest because the highest number of hydrogen bonds are formed that decided about the formation of an adsorbed film around the dispersed particle.     

Acrylonitrile-styrene-acrylate particles with different acrylonitrile contents for improving the toughness of poly(vinyl chloride) resin

Poly(butyl acrylate) grafted styrene and acrylonitrile copolymer (PBA-g-SAN, ASA) with core–shell structures were prepared by emulsion polymerization technology to improve the toughness of the poly(vinyl chloride) (PVC). The mechanical properties of the PVC/ASA blends were investigated. The notch impact strength of the PVC/ASA blend could reach 1200 J/m when the 13 phr ASA was added to the PVC. This was several times more than pure PVC resin. Scanning electron microscopy analysis results indicated that the improvement in impact strength of the PVC/ASA blend was attributed to shear yielding induced by ASA particles. Additionally, subtle changes in the ratio of monomers in the shell layer led to significant fluctuations in the mechanical properties of the composites. Dynamic mechanical analysis showed that the intermolecular interaction forces between ASA particles and PVC resins played a key role in improving the toughness of PVC/ASA blend.     

聚氯乙烯粉体表面结构对加工工艺的影响

研究了不同PVC粉体颗粒的结构特性，分析了粉体表面形态差别对树脂表观密度、增塑剂吸收率等基本性能及加工工艺（特别是对粉体的配混工艺）的影响，认为颗粒有拖尾现象的PVC粉具有较低的塑化温度及较好的塑化能力，在配混过程中出为温度应相应降低。     

水滑石和锡酸锌复合改性增塑聚氯乙烯的燃烧特性

采用原位悬浮聚合制备了水滑石和锡酸锌复合改性的聚氯乙烯（PVC）树脂,研究了水滑石和锡酸锌在PVC基体中的分散及其含量对邻苯二甲酸二异辛酯（DOP）增塑PVC极限氧指数、燃烧烟密度的影响。发现通过原位聚合可以实现水滑石和锡酸锌粒子的良好分散;DOP含量增加使PVC的极限氧指数降低,燃烧烟密度增加;而水滑石和锡酸锌含量增加,使增塑PVC的极限氧指数提高,燃烧烟密度降低。     

聚丙烯酸酯/TiO2复合粒子对PVC性能的影响

采用扫描电子显微镜,差示扫描热仪和高压毛细管流变仪,研究了聚丙烯酸酯/TiO_2复合粒子改性PVC的形貌、玻璃化温度和流变性能；结合力学性能测试,研究了复合粒子改性PVC的耐紫外光性能。结果表明：随着复合粒子用量的增加,PVC的玻璃化温度呈下降趋势；加入质量分数为3%的复合粒子,能改善PVC的流动性能,且使PVC呈现韧性断裂特征；与没有添加复合粒子的PVC相比,复合粒子改性PVC经紫外光辐照后的力学性能保持率较高,复合粒子能有效提高PVC的耐紫外光能力。