Interaction of cation-exchange membrane with polycation. II. Poly(N-alkyl-4-vinylpyridinium halides)

The effect of the hydrophile–lipophile balance (HLB) of poly(N-alkyl-4-vinylpyridinium halides) (PAVP) on the interaction between PAVP and the cation-exchange membrane was elucidated by using various alkyl groups: methyl, ethyl, octyl, and so on. In the electrodialytic concentration of sea water by using the membrane on which PAVP has been adsorbed or ion-exchanged, the ratio of monovalent cations to total cations in the concentrated brine, β (Na+K), is almost same at the initial stage in species of PAVP. However, the deterioration ratio of β(Na+K) is smaller with decreasing HLB. In order to obtain the large value of β(Na+K), poly(N-methyl and dodecyl-4-vinylpyridinium chloride) (PMDVP), was investigated. PMDVP, of which the ratio of pyridinium groups quaternized with 1-bromododecane to total pyridinium groups (Qd) is about 40%, shows high initial value of β(Na+K) and its good durability.     

氯化N-苄基-4-乙烯基吡啶聚合物的抗菌活性

氯化N-烷基-4-乙烯基吡啶聚合物,简称可溶性PVP,是一类具有高活性、低毒性和诸多潜在的特殊用途的季铵盐抗菌材料.本研究对聚-N-苄基乙烯基吡啶进行了合成与提纯,并对其在不同物理化学条件下抗菌性能差异进行了研究,结果表明温度、溶液条件等因素的变化对于样品的抗菌性能有重大影响.     

Poly(vinyl chloride) thermal stability. I. Evaluation by melt rheology

Capillary rheometry is used to characterize the thermal stability of poly(vinyl chloride). By isothermally extruding the polymer melt at constant shear rate, apparent viscosity–time relationships are obtained having three distinct regions: (1) obtainment of equilibrium viscosity, (2) constant viscosity, and (3) rapidly changing viscosity. During regions 2 and 3 the polymer extrudate gradually changes in color from water clear to black. These characteristic regions are related to the temperature of extrusion by Arrhenius plots. An activation energy of 40 kcal./g.-mole was calculated for the decomposition of PVC. Infrared spectroscopy, thermal gravimetric analysis, and intrinsic viscosity experiments are used to corroborate the results of the melt flow data.     

Properties of a cation-exchange membrane adsorbed or ion-exchanged with hexadecylpyridinium chloride

Some electrochemical properties of a cation-exchange membrane that had been adsorbed or ion-exchanged with hexadecylpyridinium chloride were observed. Two observations were made: (1) current/voltage curves (2) electric resistance of the membrane during the electrodialysis, and current efficiency of cations.Adsorption of or ion-exchange with hexadecylpyridinium chloride was carried out by immersion of the membrane in an aqueous solution of hexadecylpyridinium chloride for a given period.As the period of immersion of the membrane in the solution of hexadecylpyridinium chloride increased, the voltage of current/voltage curves remarkably increased at low cd. The current/voltage curve of the membrane immersed more than 16 h was different from that immersed less than 16 h. When the membrane which had been adsorbed or ion-exchanged with hexadecylpyridinium chloride was used in electrodialysis, the electric resistance of the membrane increased remarkably, and showed a maximum value during the electrodialysis as the immersion period increased. These phenomena are attributable to the transformation of the cation-exchange membrane to the bipolar type ion-exchange membrane and then the transformation of the bipolar type to the amphoteric type because hexadecylpyridinium ion, in the membrane's structure, functions as fixed ion-exchange group.     

Poly(vinyl chloride) composition. I. Mechanical properties and structure of poly(vinyl chloride) and fire-retardant additives

Natural, activated, and modified microzeolites were studied individually and in combination with ammonium sulfamate as high-melting dispersed additives. The strength—deformation properties of poly(vinyl chloride) were improved within the interval of 3–8 wt % additive. The strengthening effect due to the considered dispersed additives can be ascribed to the optimal adhesive interaction of the phase-boundary surface and to the formation of a partially ordered dispersed phase. The tetrahedral configuration of the modified microzeolite that contains 3.5–4% zinc in its crystal lattice remains unchanged, but exhibits a reduced birefringence. These relationships are of exceptional importance for the use of poly(vinyl chloride). The introduction of certain amounts of the additives improves the melt flow of the polymer and facilitates the processibility of the compositions. © 1993 John Wiley & Sons, Inc.     

聚羟基烷酸酯改性聚氯乙烯的研究

通过熔融共混的方法分别制备了聚氯乙烯/邻苯二甲酸二辛酯/聚羟基烷酸酯（PVC/DOP/PHA）和PVC/PHA共混物。研究了PHA逐步代替DOP对共混物力学性能和熔体流动性能的影响规律,利用扫描电子显微镜对所制备的试样进行微观结构分析。结果表明,随着共混体系中PHA用量的增加和DOP的等量减少,与PVC/DOP共混物相比,PVC/DOP/PHA共混物的拉伸强度由21 MPa提高至42 MPa,断裂伸长率先增加而后降低,在PHA含量为10.7 %(质量分数,下同)时出现极大值(350 %);在PVC/PHA体系中,PHA含量增加,PVC/PHA共混物的力学性能及熔体流动速率都显著提高,说明PHA可以作为PVC的一种有效的绿色增塑剂和增韧剂。     

Anionic graft copolymers. I. Poly(vinyl chloride)-g-polystyrene. Preparation and characterization

Graft copolymers of PVC-g-PS of controlled branching were prepared by carbanionic deactivation. The reaction products were characterized mainly by GPC. It appears that secondary reactions affect the efficiency of the grafting, chiefly at low ratios of polystyrene to poly(vinyl chloride). Techniques of grafting and analyses are discussed.     

Poly(4-vinylpyridine) Derivatives with Diphosphine Complexes of Gold(I)

The reaction of poly(4-vinylpyridine), P4VP, with complexes [Au₂(O₂CCF₃)₂{μ-Ph₂P(CH₂) _n PPh₂], n = 1–6, gives the corresponding complexes [(P4VP){Au₂(μ-Ph₂P(CH₂) _n PPh₂)} _x ](CF₃CO₂)_2x . Structural features of the polymers were deduced by study of their powder X-ray diffraction properties, aided by parallel studies of the model t-butylpyridine complexes [Au₂(μ-Ph₂P(CH₂) _n PPh₂)(NC₅H₄-4-t-Bu)₂](CF₃CO₂)₂.     

Grafted polymers from poly(4-vinylpyridinium) salts

4-Vinyl pyridine can be added via its vinylic double bond to the quaternary nitrogen atom of poly(4-vinylpyridinium chloride). When this reaction is carried out successively, model grafted polymers with grafts of a constant length with a known number of electric charges, have been obtained. Potentiometric measurements, infra-red and ¹H n.m.r. spectroscopic studies confirm the structure of the polymers.     

PVC/EVA共混物的研究

本文研究了混炼温度和时间对PVC/EVA共混物抗冲性能的影响,发现加入聚乙烯,共混体系的抗冲击强度能进一步提高.用TEM观察了PVC/EVA的形态结构,采用Brabender塑化仪和毛细管流变仪研究了共混物的塑化和熔体流变行为.通过计算机对实验结果进行二元线性回归,建立了共混物的熔体粘度与剪切应力和温度相关联的数学模型.     

聚甲基丙烯酸甲酯包覆纳米CaCO3改性聚氯乙烯研究

研究了聚甲基丙烯酸甲酯(PMMA)包覆纳米CaCO3复合粒子填充聚氯乙烯(PVC)复合材料的加工塑化和力学性能，并与未改性纳米CaCO3的改性效果进行比较。结果发现，填充纳米CaCO3使PVC平衡扭矩和平衡熔融温度均会有所提高，填充未改性碳酸钙增加更大，填充PMMA包覆CaCO3使材料冲击性能提高的幅度大于填充未改性纳米CaCO3，而拉伸强度下降幅度较小。当PMMA包覆CaCO3填充量为8％时缺口冲击强度增加到未改性PVC的194％。冲击缺口断面形态分析表明，采用PMMA包覆CaCO3时，纳米CaCO3在PVC基体中分散均匀、团聚少。     

Removal of virus from water by filtration using microporous membranes made of poly(N-benzyl-4-vinylpyridinium chloride)

Two types of microporous filter materials were developed for removing virus from water by using poly(N-benzyl-4-vinylpyridinium chloride) that captures virus in water. Conventional ultrafiltration using one to three sheets of 145-μm-thick cellulose nitrate membrane with a pore size of 0.45 μm and coated with 1.7 mg/g of poly(N-benzyl-4-vinylpyridinium chloride-co-styrene) showed 99.4–99.998% removal (2.2–4.7 log₁₀-unit reduction in concentration) of bacteriophage T4, whereas the control experiments using noncoated membrane showed 91–96% removal (1.0–1.4 log₁₀-unit reduction in concentration) of the virus. A composite 360-μm-thick microporous membrane with a pore size of 20 ¨︁m was prepared that consisted of connected minute beads of 1.7 ¨︁m in diameter made of crosslinked poly(N-benzyl-4-vinylpyridinium chloride) and reinforced by a nonwoven cloth. Simple filtration using one sheet of the composite membrane at 34.2cm/h showed 99.96–99.9995% removal (3.4–5.3 log₁₀-unit reduction in concentration). The virus was not detected in the filtrate when two sheets of the composite membrane were used. © 1996 John Wiley & Sons, Inc.     

马来酸酐接枝改性氯化聚氯乙烯的制备及其在PVC中的应用

采用固相法制备马来酸酐接枝氯化聚氯乙烯(CPVC-g-MAH),得到了接枝率达2.91 %的CPVC-g-MAH,并对其进行了性能测试,探讨了聚氯乙烯(PVC)/CPVC-g-MAH共混物的冲击性能和加工性能,与PVC/氯化聚氯乙烯(CPVC)共混物进行对比以观察改性效果。结果表明,CPVC-g-MAH的热性能较CPVC有较大提高;PVC/CPVC-g-MAH共混物的冲击性能比PVC/CPVC共混物有所提高,而平衡转矩有所降低,说明CPVC-g-MAH相比于CPVC对PVC共混物加工性能改善效果更加明显。     

Poly(N-ethyl-4-vinylpyridinium bromide)–sodium dodecyl sulfate complexes. Formation and supramolecular organization in salt containing aqueous solutions

Formation and supramolecular organization of poly(N-ethyl-4-vinylpyridinium bromide) (PEVP)–sodium dodecyl sulfate (SDS) complexes in aqueous-salt solutions have been studied. PEVP samples of three polymerization degrees (P_w = 570, 1200 and 2350) were used. For PEVP of lower polymerization degree (P_w = 570) only insoluble complexes were observed in the whole range of the reaction mixture composition studied: Z = [SDS]/[PEVP] ≤ 1. For PEVP of higher polymerization degrees (P_w = 1200 and 2350), water-soluble complexes are formed up to a critical value of the reaction mixture composition, Z, that is similar for both PEVP fractions. It was found that water-soluble complex species are either molecularly dispersed (i.e. each complex particle comprises only one macromolecule) or aggregated (includes about 40 polymer chains and 20,000 surfactant ions) depending on the complex composition. Complex composition, in its turn, was shown to be determined by PEVP polymerization degree and the reaction mixture composition.     

Poly(acrylamide-chitosan) Hydrogels: Interaction with Surfactants

Semi-interpenetrating hydrogels were prepared from hydrophilic acrylamide and cationic natural biopolymer chitosan, N,N¹-methylenebisacrylamide and water-soluble redox initiating system (ammonium persulfate/N,N,N¹,N¹-tetramethylethylenediamine). The interaction of these hydrogels with different surfactants such as sodiumdodecylsulphate (SDS, anionic), N-cetyl N,N,N-trimethyl ammonium bromide (CTA, cationic) and Tween20 (T20 non-ionic) was studied. The chemical structure of the hydrogels treated with surfactant was characterized by FTIR spectroscopy and the morphology of hydrogels was characterized by scanning electron microscopy (SEM). The thermal properties of surfactant-treated hydrogels were evaluated by TGA analysis.     

Poly (vinyl chloride) processing morphology

This paper describes how morphology of PVC changes in the Brabender mixing head. At the range of temperatures used for PVC processing, the Brabender torque-time curve shows minimum torque and maximum torque. The minimum torque is associated with a breakdown of 150 μm PVC grains and 10 μm agglomerates resulting in the release of the 1μm primary particles. The torque increases from minimal interaction between primary particles to the point where primary particles agglomerate at maximum torque so that fibriles can be formed when PVC samples are swollen in acetone and sheard. Further heating reduces the viscosity resulting in lower torque even though residual primary particles still exist with much particle to particle interaction. Primary particle structure disappears at about 215° C with complete melting.     

Poly(vinyl chloride)/plasticizer-mixture interactions. Part I. Phthalate ester mixtures

Flory-Huggins interaction parameters, χ, have been determined as a function of plasticizer composition for poly(vinyl chloride) in various binary mixtures of phthalate ester plasticizers using a method involving the micro-determination of the temperature at which PVC particles in excess plasticizer appear to melt. An optimum composition at which χ goes through a minimum was found to exist for some of the systems. A good correlation between the apparent melting temperature t_m and χ for the neat plasticizers with PVC was also established.     

弹性体改性软质聚氯乙烯性能的研究

讨论了不同品种的弹性体对软质氯乙烯的改性结果,包括不同品种和不同含量的弹性体对ＰＶＣ力学性能等性能的影响,实验了得到了性能较好的改性ＰＶＣ软质材料。     

Synthesis of Xanthene Derivatives in Presence of Poly(4-vinylpyridinium) Perchlorate as a Solid Acid under Grinding and Solvent-Free Conditions

In this article, the synthesis of xanthene derivatives catalyzed by poly(4-vinylpyridi-nium) perchlorate is presented under grinding and solvent-free conditions. This methodology consistently has the advantages of excellent yields and the fast rate of reactions. The catalyst can be recovered by simple filtration and used for several times without a significant leaching and loss of catalytic activity.     

给水管用PVC的改性研究

采用活性碳酸钙和甲基丙烯酸甲酯-丁二烯-苯乙烯三元接枝共聚物(MBS)对PVC进行改性,研究了二者对改性PVC抗冲击性能的影响.结果表明,活性碳酸钙和MBS的加入,改性PVC的抗冲击性能可提高17.3％,改性PVC管在低温下的抗冲击性能得到明显提高.