PVC/PVDF/PMMA共混膜的研制

采用剪切黏度法对聚氯乙烯(PVC)/聚偏氟乙烯(PVDF)/聚甲基丙烯酸甲酯(PMMA)体系的相容性进行研究,结果表明,该体系为部分相容体系,在此基础上采用稀溶液黏度法对各共混配比的相容性进行预测.对相容性较好的PVC/PVDF/PMMA共混体系由相转化法制备共混膜,并用扫描电镜对共混膜的形态结构进行了观察.对共混膜的...     

聚氯乙烯共混超滤膜研究

利用溶解度参数法、宏观状态分析、黏度法、相差显微镜观察法,DSC(差示扫描量热计)等手段研究了PVC／PVB二元共混体系的相容性．结果表明,PVC和PVB共混体系在一定配比范围内为部分相容,且相容性较好,该共混体系明显改善了PVC的亲水性,而且利用SEM扫描电镜从膜结构方面对PVC／PVB共混膜性能的提高进行了分析．     

PVC/PS熔融纺丝体系的相容性

针对聚氯乙烯(PVC)耐热性和韧性差的缺陷,利用共混-交联协同技术对PVC进行改性,通过熔融纺丝法制备了PVC改性纤维,采用红外、动态力学分析仪、差示扫描量热仪和扫描电镜对纤维PVC/PS体系的相容性进行了研究。聚苯乙烯(PS)能有效地提高PVC的韧性,在交联助剂苯乙烯单体和三乙醇胺的作用下,过氧化二异丙苯(DCP)可有效地交联PVC,苯乙烯单体与大分子自由基发生接枝聚合,生成的接枝聚合物可作为就地增容剂改善PVC/PS体系的相容性。     

PVC/PAN共混膜的制备与性能

采用溶液相转化法制备了聚氯乙烯(PVC)/聚丙烯腈(PAN)共混膜,研究了(PVC)/(PAN)共混体系的相容性,并通过红外光谱(FT-IR)、扫描电子显微镜(SEM)等对PAN水解前后共混膜结构、形貌和性能进行了表征与分析。结果表明,(PVC)/(PAN)为部分相容体系,在成膜过程中产生明显界面微孔结构;共混膜中的PAN发生水解后,生成大量酰胺、羧酸、羧酸盐等亲水基团,改善了共混膜的亲水性(膜的水接触角从87.48°降低到65.12°),提高了共混膜的通透性(膜的纯水通量从84.17 L/(m2.h)升高到343.7 L/(m2.h))。     

PSf/SPES共混相容性及其对膜形态结构和性能的影响规律

针对聚砜(PSf)和磺化聚醚砜(SPES)聚合物共混体系相容性,首先通过混合焓法计算预测并用差示扫描量热法(DSC)进行了分析.结果表明,二者为部分相容体系,且相容性随共混比的增大呈下降趋势.此外,以N,N-二甲基乙酰胺(DMAc)为溶剂,采用浸没沉淀相转化法制备出PSf/SPES共混平板超滤膜,系统研究了共混相容性对膜形态结构及性能的影响规律.结果表明,当PSf/SPES共混比小于90/10(质量比)时,聚合物共混具有较好的相容性,所制备共混膜的断面为梯度分布的海绵网络孔结构,且亲水性、表面孔孔径、孔隙率和纯水通量等均随着共混比的增大而增大.其中,当PSf/SPES=92/8时,膜的纯水通量达到1 397L/(m2·h),对牛血清蛋白(BSA)截留率为85%.随着PSf/SPES共混比进一步增加,共混体系相容性变差,膜的断面出现指状孔结构,BSA截留率显著下降.     

PVC/PS熔融纺丝体系的相容性EI北大核心

针对聚氯乙烯(PVC)耐热性和韧性差的缺陷,利用共混-交联协同技术对PVC进行改性,通过熔融纺丝法制备了PVC改性纤维,采用红外、动态力学分析仪、差示扫描量热仪和扫描电镜对纤维PVC/PS体系的相容性进行了研究。聚苯乙烯(PS)能有效地提高PVC的韧性,在交联助剂苯乙烯单体和三乙醇胺的作用下,过氧化二异丙苯(DCP)可有效地交联PVC,苯乙烯单体与大分子自由基发生接枝聚合,生成的接枝聚合物可作为就地增容剂改善PVC/PS体系的相容性。     

聚丙烯腈/聚甲基丙烯酸正丁酯共混体系的相容性及流变性能

采用溶解度参数法预测聚丙烯腈(PAN)/聚甲基丙烯酸正丁酯(PBMA)为部分相容体系,并通过黏度法、红外光谱法(FT-IR)、动态力学分析法(DMA)和差示扫描量热法(DSC)进一步判断PAN与PBMA的相容性。结果表明,二者属于部分相容体系,与理论预测相符。以N,N-二甲基乙酰胺(DMAc)为共溶剂,研究了PAN/PBMA共混溶液的流变性能,研究表明,共混溶液的流动性与其组成、温度以及浓度有关,通过改变上述因素可以有效调控共混溶液的流动性,这为后续制备具有吸附功能的PAN/PBMA共混纤维奠定了理论基础。     

PVC／NBR共混物微观结构与性能的关系

本文测定了两种丁腈橡胶(NBR-29和NBR-40)与聚氯乙烯(PVC)共混物的应力-应变行为和冲击性能,用动态力学分析(DMA)与透射电子显微镜(TEM)研究了共混物的相容性和形态结构,并且讨论了形态结构与性能的关系。研究结果表明:NBR-29对PVC有优良的增韧改性作用,PVC/NBR-29共混物为半相容的两相体系,NBR-40对PVC则无增韧改性效果,PVC/NBR-40共混物为非均匀的相容体系。     

聚偏氟乙烯/聚氯乙烯共混中空纤维膜的研制

实验表明PVDF/PVC共混体系是部分相容体系,且在共混比是7∶3时,相容性最好.还讨论了不同聚合物配比,不同溶剂,不同添加剂对共混膜性能的影响,并进行了分析.     

PVA/HPC相容性及共混膜的性能

共混改性是提高材料性能的简便而有效的方式,文中以聚乙烯醇(PVA)和羟丙基纤维素(HPC)为基本成膜材料,通过制备不同配比的共混溶液,探讨了PVA/HPC共混体系的相容性,并对共混膜的结构和性能进行了初步表征。稀溶液黏度法和扫描电镜分析表明,共混体系中PVA含量较多(80%)时,共混膜呈现均一的相态结构,共混体系为相容体系;傅立叶红外光谱和热重分析显示,PVA/HPC共混体系中存在的氢键作用提高了共混体系的热稳定性。     

Study of Polymer Blends with Sub-cluster Theory Part 2 Comparison of PVC/ABS, PVC/SBS Blends

Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters     

聚甲基丙烯酸N,N-二甲氨基乙酯复合纳滤膜的制备

以AIBN为引发剂,采用本体聚合的方法制备了聚甲基丙烯酸N,N-二甲氨基乙酯(PDMAEMA),并采用中空纤维超滤膜技术滤除PDMAEMA水溶液中的低聚物和未反应的单体.以聚砜(PSf)超滤膜为基膜,以所精制的PDMAEMA为水相涂层液,以对二氯苄的正庚烷溶液为有机交联剂,利用界面聚合的方法制备了PDMAEMA/PSf荷正电复合纳滤膜.实验重点研究了PSf基膜和单体浓度、水相pH值及浸涂时间、水相沥干时间、交联反应时间等条件对所制备纳滤膜分离性能的影响,确定了较优的制膜条件.所制备的荷正电纳滤膜对1g/LMgSO4水溶液(0.8MPa,30℃)的截留率为86.7%,水通量为8.4L/(m2.h).     

Miscibility and shape memory property of poly(vinyl chloride)/thermoplastic polyurethane blends

The miscibility and the shape memory effect of PVC blends with segmented thermoplastic polyurethanes (TPUs), synthesized from diol-terminated polycaprolactone (PCL), hexamethylene diisocyanate, 4,4-dihydroxy biphenyl, were studied. PVC was miscible with PCL segment in TPU and the glass transition temperature of this miscible amorphous domain varied smoothly with composition. When PVC was blended with TPU by the weight ratio of 8/2, the hysterisis in repeated cyclic tensile test was reduced compared with PVC. However, in 6/4 blends, unrecoverable permanent deformation was increased compared with PVC. Dynamic mechanical properties were examined to explain these results.     

Effect of coupling agent and nanoclay on properties of HDPE,LDPE, PP,PVC blend and Phargamites karka nanocomposite

High density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP) and poly(vinyl chloride) (PVC) were solution blended by using a mixture of xylene and tetrahydrofuran as solvent and polyethylene-co-glycidyl methacrylate (PE-co-GMA) as compatibilizer. The minimum ratio of solvents to obtain a homogenous solution was optimised. Wood polymer composites (WPC) were prepared by using solution blended polymer, wood flour and nanoclay. X-ray diffraction studies of WPC treated with 1 and 3 phr nanoclay showed higher exfoliation compared to WPC treated with 5 phr nanoclay. TEM study also supported the above findings. FTIR studies indicated an interaction between wood, PE-co-GMA and clay. SEM study indicated an increase in miscibility among polymers due to addition of PE-co-GMA as compatibilizer. Thermal stability improved on addition of clay to the WPC. WPC treated with 3 phr clay showed highest mechanical properties. Hardness and water absorption were improved significantly with the addition of nanoclay to wood/polymer composite.     

Properties and Application of Nanocrystalline Poly (vinyl chloride)

The structure and properties of nanocrystalline PVC were investigated. The crystalline region of nanocrystalline PVC was observed by TEM to be 80 nm. The melting point of nanocrystalline PVC was found to be 128℃which is obviously lower than typical PVC (210℃). The X-ray diagrar indicated that the crystal existed in nanocrystalline PVC. The evident effect of self-plasticizing and reinforcement appeared when nanocrystalline PVC was added. The optimum amount for self-plasticizing is about 10%. The maximal impact strength of 95.1 kJ/m2 was achieved by adding 20% nanocrystalline PVC and tensile strength with 56.2 MPa which was 122% of pure PVC was obtained after adding 5% nanocrystalline PVC.     

聚氯乙烯/氧化石墨烯薄膜的力学性能和热稳定性能

通过溶液共混法制备了氧化石墨烯(GO)分散均匀的聚氯乙烯(PVC)/GO纳米复合薄膜,研究了薄膜的力学性能和热稳定性能。结果表明,微量GO能大幅度提高PVC的模量和拉伸强度,且保持较高的断裂伸长率。在PVC中添加质量分数为0.12%的GO,PVC的拉伸强度提高63%,杨氏模量提高20%;添加量为0.60%时,PVC的拉伸强度提高125%,杨氏模量提高126%.添加GO还能提高PVC的起始分解温度、最大分解温度以及PVC的成碳量。GO片层具有较高的强度和模量、GO在高分子基体内的均匀分散、GO和PVC之间较强的相互作用、GO与PVC的层状结构,是其力学性能提高的主要原因.     

Extent of immiscibility in the ettringite–thaumasite system

Solid solutions between thaumasite and the related phase ettringite were prepared and characterised by X-ray diffraction and infrared spectroscopy. A miscibility gap in the solid solution is identified and defined. Crystallographically, the miscibility gap is identified as a gap in the unit cell dimensions of the solid phases formed between c20.95 (10.475) and c21.3 Å. A combination of quantitative X-ray powder diffraction and infrared spectroscopy enabled us to define the miscibility gap in terms of Al:Si ratio. Ettringite can accept the replacement of 1/2 its Al by Si, while thaumasite tolerates little or no Al in its structure.     

Sulfonated polyethersulfone-based membranes for metal ion removal via a hybrid process

Membranes are being increasingly used as an economic alternative for wastewater treatment compared to conventional methods. Ultrafiltration membranes are widely used in metal ions’ rejection. Sulfonated Polyethersulfone (SPES)/polysulfone (PSf) blend flat sheet membranes are prepared using polar solvent N-methyl-2-pyrrolidone (NMP) by the dry–wet phase inversion technique. Polyethylene glycol (PEG-200) is used as a non-solvent additive in the casting solution. The effect of PSf/SPES blend ratio on the morphology, hydrophilicity, water content, porosity, hydraulic resistance, pure water flux, compaction, and molecular weight cut-off (MWCO) of the prepared membranes was studied and found to be improved significantly by the incorporation of SPES in the dope solution. Scanning electron microscopy (SEM) studies revealed that the membranes formed had an asymmetric structure with a thin skin layer and porous sublayer. The prepared membranes were used for rejection of Cu(II) and Zn(II) which are complexed with water-soluble chelating polymer polyethyleneimine. The results show that the order of rejection is Cu(II) ion > Zn(II) ion. Thus, it is worth mentioning that the PSf/SPES blend ultrafiltration membranes prepared in this study would offer immense potential in removal of toxic metal ion from industrial effluents.     

溶液浓度和非溶剂比例对PVC膜形貌和疏水性能的影响

目的 研究溶液质量分数和非溶剂体积分数对PVC薄膜表面形貌和疏水性能的影响,以获得具有超疏水表面的PVC薄膜。方法 以四氢呋喃为良溶剂、乙醇为非溶剂,利用非溶剂诱导相分离的原理,采用旋涂法在玻璃基底上制备超疏水的聚氯乙烯（PVC）涂膜;通过对PVC样品的疏水性、表面形貌、结晶性能和热性能进行分析,探究溶液质量分数以及非溶剂的体积分数对PVC样品性能的影响。结果扫描电镜和接触角测试表明,添加一定体积分数的乙醇使得所制备的PVC样品形成了多孔膜层以及纳米级聚合物球粒,从而提高了PVC样品的疏水性。XRD测试结果表明,添加乙醇并不会改变PVC样品的无定形结构。结论 PVC溶液质量分数对所制备PVC样品的疏水性能和表面结构没有明显影响,乙醇体积分数为30%～40%时,可形成表面水接触角大于150°的超疏水表面。