Melt elasticity behavior and extrudate characteristics of rigid poly(vinyl chloride)/epoxidized natural rubber miscible blends

A study on the melt elasticity behavior and extrudate characteristics of melts of rigid poly(vinyl chloride), PVC, and rigid poly(vinyl chloride)/epoxidized natural rubber (ENR) miscible blends were conducted. Extrusion studies were carried out in a capillary rheometer and examinations of the surface characteristics of the extrudate were made by taking photomicrographs in a scanning electron microscope. The anomalous behavior in the die swell ratio of rigid PVC arising from the particle agglomerates continued in its blends up to 50 wt% composition of ENR. Temperature independence for high ENR blends was noted for the principal normal stress difference and elastic shear modulus, when shear stress was held constant. Recoverable shear strain and die swell ratio behaved identically in terms of blend composition and processing temperature. Factors which control the extrudate distortion and melt fracture of the melts of rigid PVC/ENR systems were fusion of particle agglomerates and strength of melts. Diamond cavitations were typical of the extrudate surface of PVC melts as those of the fracture surface of the tensile failure of PVC. Conditions to obtain a smooth extrudate surface of rigid PVC melts in blends with ENR have been found to be the low ENR content, low shear rate, or stress and high processing temperature.     

Effect of surface properties on the adhesion between PVC and wood veneer laminates

The interface between plastic and wood fibers strongly influences the mechanical properties of a plastic/wood-fiber composite. This paper presents a means for evaluating the effectiveness of surface treatment on the wood-fibers in the PVC/wood-fiber composites by investigating the adhesion between PVC and laminated wood veneers. Wood veneers were first treated with γ-aminopropyltriethoxysilane, dichlorodiethylsilane, phthalic anhydride, and maleated polypropylene for surface modification. The chemical modification made on the wood surfaces was then characterized using different complementary surface analytical techniques: X-ray photoelectron spectroscopy and surface tension measurements. The surface tension was determined from the equation of state for interfacial tensions and the measured contact angles of glycerol sessile drops on the wood veneers (both untreated and treated) and on PVC using the Axisymmetric Drop Shape Analysis–Contact Diameter (ADSA-CD) approach. The adhesion property was evaluated by measuring the tensile shear strength of single lap joints between two wood veneers bonded with a PVC film. The adhesion between PVC and wood veneer laminates was significantly improved when wood veneers were treated with amino-silane, while no improvement was observed for the other adhesion promoters. Our experimental results indicate that matching the surface tension is not sufficient to ensure good adhesion between PVC and wood veneers.     

提高PVC型材表面张力的研究

在PVC型材覆膜之前,通常采用清洗剂来去除脱模剂以提高其表面张力,但清洗剂会污染环境。为了解决此问题,进行了机械抛光试验,考察了其提高PVC型材表面张力的效果。结果表明:采用软毛刷进行逆向抛光,当压人深度为5-10 mm时,可使PVC型材的表面张力达到覆膜的要求。     

Surface tension and specific volume of copper–titanium melts measured by the sessile drop method

By using non-wetted and inert calcium fluoride substrates as plates or crucibles (cups), it is possible to extend the sessile drop method and its more precise version 'large drop' method for surface tension measurement of highly chemically active alloys. The surface tension and density of copper-titanium alloys over a wide range of titanium concentration (up to 70 at%) at temperatures between 1000 and 1250°C were measured. The surface tension-concentration dependence for Cu-Ti melts deviates positively from the Zhychovitsky theoretical isotherm for ideal solutions. The compression of alloys is observed. The copper-titanium melts deviate negatively from Raoult's law. The work of adhesion of Cu-Ti melts to CaF₂ was also determined and it was found to be 820 ± 65 mJ/m² for Cu + 70 at% Ti.     

PVC薄膜自黏性研究

采用流延法制备了聚氯乙烯（PVC）自黏膜,通过数字高阻计、原子力显微镜、视频光学接触角测量仪、傅里叶红外光谱仪等研究了增塑剂邻苯二甲酸二辛酯（DOP）含量、增黏剂种类及含量、薄膜厚度、表面粗糙度、表面张力、表面析出物对PVC膜自黏性的影响。结果表明,PVC膜的自黏强度随增塑剂含量增加而增加;增黏剂的加入极大地改善了PVC膜的自黏性,其中萜烯树脂増黏效果最好;PVC膜的自黏性与薄膜的表面能有很大的关系。     

An Examination of Surface Tension of Binary Lithium Borate Melts as a Function of Composition and Temperature

Surface tensions of x Li₂O–(1− x )B₂O₃ melts, where 0≤ x ≤0.68, have been measured systematically with a ring method from respective liquidus temperatures up to about 1450 K. For all of the investigated melts, the relationship between surface tension and temperature can be well described by quadratic polynomial functions. With increasing Li₂O content, surface tension monotonously increased, whereas the temperature coefficient of surface tension increased slowly up to about x =0.1, changed sign from positive to negative at about x =0.2, and then remained negative with further increasing Li₂O content. Together with the physical properties reported in our previous work, such as density, temperature coefficient of density, and volume expansion coefficient, etc., both surface tension and temperature coefficient of surface tension have been comparatively plotted as a function of Li/B molar ratio. Differentiated from the inflections of slope in the plots of physical properties vs. Li/B molar ratio, three characteristic regions have been found in the melts of this system. Within different regions, different effects of temperature and concentration on the physical properties of melts have been observed.     

Preparation of a super-hydrophobic poly(vinyl chloride) surface via solvent-nonsolvent coating

A new simple approach was developed to obtain a super-hydrophobic PVC surface via solvent-nonsolvent coating without addition of low-surface-energy compounds. Also, the PVC film is nearly or still maintains its super-hydrophobicity when contacting with acid, alkali or salt solutions. SEM shows that compared with common smooth PVC surface, a lotus-like structure with micro- and nano-papillae was obviously observed on the hydrophobic PVC surfaces. Such a special surface microstructure may result in the super-hydrophobicity. A brief explanation to the formation of the special microstructure was put forward on the basis of diffusion, tension break and micro- and nano-phase separation.     

Study on the surface tensions of polymer melts using axisymmetric drop shape analysis

It is shown that Axisymmetric Drop Shape Analysis (ADSA) is well-suited for the study of polymer melt surface tensions. The technique is not restricted to equilibrium surface (interfacial) tensions; it is also suitable for measuring the time dependence (or kinetics) of surface tension of polymer melts. Results for three polymers, polypropylene, polyethylene, and polystyrene, at temperatures above 170°C are reported. Contrary to the well-known decrease of surface tension in low molecular weight surfactant solutions as a result of equilibration, an increase in the melt surface tension is observed under isothermal conditions.     

Influence of composition of sodium aluminoborosilicate melts containing nickel and calcium oxides on the wetting angle on platinum

The influence of the composition of sodium aluminoborosilicate melts containing nickel and calcium oxides on the wetting angle on platinum has been studied by the method of “small drop on thin thread.” It is shown that partial mutual replacement of silicon, aluminum, and boron oxides (up to 4 mol %) does not substantially change the wetting angle. The wetting angle increases after the partial replacement of these oxides by calcium oxide and decreases after their replacement by nickel oxide. Since a change in the surface tension of melts in the composition range studied is insignificant, the work of adhesion and the “glass melt-metallic substrate” interfacial tension are determined by the wetting angle. The maximum work of adhesion and the minimum interfacial tension are characteristic of melts with an increased nickel oxide content, and the minimum work of adhesion and the maximum interfacial tension are observed for melts with an increased calcium oxide content. Deceased.     

Influence of composition of sodium aluminoborosilicate melts containing nickel and calcium oxides on the wetting angle on platinum

The influence of the composition of sodium aluminoborosilicate melts containing nickel and calcium oxides on the wetting angle on platinum has been studied by the method of “small drop on thin thread.” It is shown that partial mutual replacement of silicon, aluminum, and boron oxides (up to 4 mol %) does not substantially change the wetting angle. The wetting angle increases after the partial replacement of these oxides by calcium oxide and decreases after their replacement by nickel oxide. Since a change in the surface tension of melts in the composition range studied is insignificant, the work of adhesion and the “glass melt-metallic substrate” interfacial tension are determined by the wetting angle. The maximum work of adhesion and the minimum interfacial tension are characteristic of melts with an increased nickel oxide content, and the minimum work of adhesion and the maximum interfacial tension are observed for melts with an increased calcium oxide content. Deceased.     

The viscosity of monomolecular melts of poly(vinyl chloride)

PVC melts are predicted to be homogeneous with single molecules as the stable flow units (monomolecular melts) at corresponding values of high temperatures and/or high shear stresses. Under these conditions, it is found that the zero shear viscosity in simple shearing flow of rigid compounds depends on the average molecular weight by weight to the 3.5 power for molecular weights between 24,000 and 100,000. All data measured under conditions where monomolecular melts are predicted fall on a master curve of reduced viscosity versus reduced shear rate when a relaxation time proportional to η0/c²T is used. It is, therefore, concluded that monomolecular melts of PVC compounds follow the same structure–viscosity relations as found for other linear melts in viscometric flow.     

Surface Tension of Alkaline-Earth Borates Containing 3 Mole % Potassium Oxide

The surface tensions of a series of barium, strontium, and calcium borates, each containing 3 mole % of K₂O to counteract immiscibility, were measured by a ring detachment method. The order Ca < Sr < Ba was established for surface tensions of melts containing up to 40 mole % MO (alkaline-earth oxide). Positive temperature coefficients of surface tension were observed for melts of low MO content. An interpretation of the observed inversions of surface tension from the order of ionic potential of the cations for these systems, as well as for other systems previously studied, is presented in terms of the Gibbs adsorption equation. A connection is indicated between inversions in the order of surface-tension values and the presence of positive temperature coefficients.     

大分子键合处理CaCO3的表面性质及其与PVC的界面特性

研究了以大分子键合方式包覆处理CaCO3粉末的表面性质及其填充PVC的界面性质和力学性能,结果表明:①与未处理的CaCO3相比,所有改性CaCO3的表面张力均明显下降,其中表面张力的极性分量大幅度下降,但色散分量略有提高,与PVC的界面张力及其极性分量和色散分量均下降;②用大分子弹性体键合方式处理的CaCO3对PVC填充材料具有明显的增韧效果,其效果优于铝酸酯偶联剂,显示出良好的应用前景。     

Influences of individual and composed poly(vinyl alcohol) suspending agents on particle morphology of suspension poly(vinyl chloride) resin

Effects of individual and composed poly(vinyl alcohol) (PVA) suspending agents on the particle morphology of poly(vinyl chloride) (PVC) resins were investigated and discussed in the view of PVA absorption at the oil/water interface and interfacial behavior. It was shown that the percentage and surface coverage of PVA at the oil/water interface decreased with the increase of the degree of hydrolysis (DH) of PVA in the DH range of 70–98 mol %, while the interfacial tension of VC/PVA aqueous solution increased linearly with the increase of DH of PVA. PVC resin with more regular particle shape, increased agglomeration and fusion of primary particles, lower porosity and higher bulk density, was prepared by using PVA with a higher DH as a suspending agent. This was caused by the occurrence of drop coalescence at the very early stage of VC polymerization, the increase of particle shrinkage, and the lower colloidal protection to primary particles. It was also shown that the interfacial tension of VC/water in the presence of composed PVA suspending agents varied linearly with the weight composition of the composed PVA suspending agents. The particle properties of PVC resin prepared by using the composed PVC suspending agents were usually situated in between the properties of PVC resins prepared by using the corresponding individual PVA suspending agent. The particle morphology and properties of PVC resin could be controlled by the suitable choice of the composed PVA suspending agents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3848–3855, 2003     

Effect of the 3<Subscript>d</Subscript>-Transition Metal Oxides on the Surface Tension of the Sodium Silicate Melt

The effect of 3d-transition metal oxides on the surface tension of the 17.5Na₂O · 82.5SiO₂ · nRO (R = Mn, Fe, Co, Ni, Cu; n = 0.1–10) melt is revealed in the temperature range 1250–1450°C. It is found that cobalt oxide in the range of low concentrations (0.1–1.0 mol %) is characterized by anomalously low values of the surface tension. In the case of CoO oxide, the surface tension increases as the temperature increases and the melts containing MnO, FeO, NiO, and CuO oxides have negative temperature coefficients. In the range of high concentrations of the studied oxides (n = 10 mol %), the surface tension of melts decreases with an increase in the atomic number of cation in the sequence Mn → Fe → Co → Ni → Cu.     

Dissolution of Alumina-Silicate Refractories in Slag Melts

Experimental relationships between the rate of dissolution of an alumina-silicate refractory and the physical properties of slag melts (viscosity, surface tension, wetting angle) at different refractory–slag contact times are considered.     

Surface Tension and Density of Bismuth Germanate Melts as a Function of Composition and Temperature

The surface tension and density of x Bi₂O₃–(1− x )GeO₂ (BGO) melts have been measured systematically from their respective melting points up to around 1480 K within 0.25≤ x ≤0.86. With the addition of Bi₂O₃, the density of this system increased smoothly with a positive curvature. Deviation of molar volume from ideality of this system melts decreased firstly, past a minimum at about x =0.4, and then increased. Partial molar volumes of Bi₂O₃ and GeO₂ have also been calculated based on the measured density data and compared with those of a binary bismuth borate system. On increasing the content of Bi₂O₃, the surface tension of BGO melts increased slowly when x <∼0.40, past a maximum at about x =0.50, and then decreased rapidly. In addition, the temperature coefficient of surface tension remained positive within the lower content range of Bi₂O₃, changed sign from positive to negative at about x =0.38, and then was almost independent of the composition within the measured temperature range when the Bi₂O₃ content was increased further.     

PVB边角料用于硬质聚氯乙烯的改性研究

利用汽车夹层玻璃生产中所产生的大量边角料聚乙烯醇缩丁醛(PVB)来改性硬质聚氯乙烯(PVC-U),以提高PVC-U的冲击性能,测试了PVC-U/PVB共混物的冲击性能、拉伸性能及加工性能,并用场发射环境扫描电子显微镜(SEM)对其进行了断面形貌分析.结果表明,当100份PVC-U中加入5份PVB时,PVC-U/PVB体系的相容性较好,其冲击性能是纯PVC-U的2倍以上,而体系的拉伸性能变化不大,同时加工性能也得到了很好的改善.     

Rheological properties of poly(vinyl chloride) / epoxidized natural rubber blends. Part II: The effect of processing variables

The effect of processing variables on the rheological properties of PVC/ENR blends was investigated. The role of crosslinking in determining the flow behavior of blends was also examined by means of dynamically cured blends. It was found that PVC/ENR blends yield melts that are power law fluids. The flow of the melts improves with an increase in temperature and shear rate. However, the introduction of crosslinks reverses this trend, although under more rigorous conditions, the influence of crosslinks is superseded, and subsequently, flow becomes shear rate and temperature dependent. PVC/ENR systems also manifested elastic phenomena. The dependence of the elastic phenomena such as die swell and melt fracture on L/D ratio of the die was demonstrated.     

Influence of additives on interfacial phenomena during film formation of powder coatings

Film formation of powder coatings is illuminated from a physico-chemical point of view. Significant parameters influencing the film formation of powder coatings are surface (wetting) tension and viscosity of the polymer melt formed during the film formation process. A newly developed measuring device for the investigation of wetting at elevated temperatures is presented. This device allows systematic investigations of the temperature dependence of the wetting tension of powder coating binder systems. By combining analytical and surface tension measurements, it is possible to gain new information about the mechanism of action of additives in these melts. Hohe Stra?e 6, D-01069 Dresden, Germany.