Influence of lanthanum stearate as a co-stabilizer on stabilization efficiency of calcium/zinc stabilizers to polyvinyl chloride

Influence of lanthanum stearate (LaSt₃) as a co-stabilizer on stabilization efficiency of calcium stearate (Ca)/zinc glutarate (Zn) stabilizers to polyvinyl chloride (PVC) at 180 °C in air was investigated. The results showed that combination of LaSt₃ with Ca/Zn stabilizers presented an obvious improvement of stabilization efficiency to PVC compared with the Ca/Zn stabilizers. Moreover, addition of LaSt₃ to the Ca/Zn stabilizers could significantly enhance static stability time of PVC. Incorporation of 2 phr LaSt₃ co-stabilizer to PVC containing 3 phr Ca/Zn stabilizers resulted in marked increase of onset degradation temperature and reductions in average degradation rate as well as the dynamic storage modulus (G′) and loss modulus (G″) at 180 °C. Influence of Ca/Zn ratio on tensile strength of PVC in the absence or in the presence of LaSt₃ was discussed in detail. At low Ca/Zn ratios LaSt₃ had an obvious improvement in the tensile strength, while at high Ca/Zn ratios this effect became inconspicuous.     

4-Nitrophthalic esters as plasticizers for polyvinyl chloride

The properties of polyvinyl chloride (PVC) compositions plasticized with dibutyl and di-(2-ethylhexyl)esters of phthalic and 4-nitrophthalic acids were investigated. The result of physical and mechanical tests and dynamic mechanical analysis of samples of polymer compositions demonstrated that an introduction of a nitro group and an increase in the polarity of the plasticizer leads to a decrease in its volatility from polymer films, an increase in the strength and elasticity of the samples. Quantum-chemical calculations of systems simulating polymer-plasticizer solvation interactions revealed the possibility of enhancing intermolecular interactions with the participation of nitrophthalates. It is noted that the method of PVC film formation (from solutions or from melts) affects their properties.

     

Novel antimicrobial organic thermal stabilizer and co-stabilizer for rigid PVC

Biologically active N-benzoyl-4-(N-maleimido)-phenylhydrazide (BMPH) was synthesized and its structure was confirmed by elemental analysis and various spectral tools. It was examined as a thermal stabilizer and co-stabilizer for rigid poly (vinyl chloride) at 180 °C in air. Blending BMPH with reference samples in different ratios greatly lengthens the thermal stability value and improves the extent of discoloration of PVC. TGA confirmed the improved stability of PVC in presence of the investigated organic stabilizer. GPC measurements were done to investigate the changes occurred in the molecular masses of the degraded samples of blank PVC and PVC in presence of the novel stabilizer. BMPH showed good antimicrobial activity towards two kinds of bacteria and two kinds of fungi.     

Ester plasticizers for polyvinyl chloride

The review covers information from patents and papers that have been published in the past 5 years and deal with the synthesis of ester plasticizers for polyvinyl chloride. The main trends in the progress of this field are analyzed. Data on new esterification catalysts are presented. Particular attention is paid to plasticizers derived from terephthalic acid, which show promise for replacing toxic dioctyl phthalate. The results of studies on synthesis and properties of nonphthalate plasticizers based on benzene, toluene, naphthalene, cyclohexane, and norbornene are considered. Synthesis methods and prospects for using plasticizers derived from renewable vegetable raw materials, namely, citrates, succinates, triglycerides, fatty acid esters, and sugar derivatives, are discussed.     

Triorganylphosphine oxides as high-performance fire retardants for polyvinyl chloride plastisols

The possibility, in principle, of using tertiary phosphine oxides with different structures as fire retardants for polyvinyl chloride plastisols was examined, and their ability to reduce the flammability of these materials was analyzed.     

Reaction of products of thermal and thermal oxidative degradation of polyvinyl chloride with barium hydroxide

The reaction of products of thermal and thermal oxidative degradation of polyvinyl chloride with barium hydroxide was studied. The degree of binding of chlorine and carbon atoms from polyvinyl chloride in reactions of barium hydroxide with hydrogen chloride and carbon dioxide formed by degradation and oxidation of the polymer was studied in relation to the hydroxide/polymer weight ratio and temperature. The activation energies of the reaction and the specific rates of formation of barium chloride and carbonate were calculated.     

Poly(propylene imine) dendrimers as plasticizers for polyvinyl chloride

Fourth and fifth generation poly(propylene imine) dendrimers and methyl and benzyl functionalized copolymers of these dendrimers are solution blended with poly(vinyl chloride) (PVC). The methyl‐derivative copolymer is observed to be dispersed in PVC as judged by optical and dynamic scanning calorimetry measurements. This dispersion leads to a substantial reduction in the glass transition temperature and a commensurate plasticization effect, demonstrating that functionalized dendrimer copolymers can successfully plasticize semicrystalline polymers. This plasticization is thought to occur as a result of additional free volume from the highly branched structure of the dendrimer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1970–1975, 2007     

The mechanical anisotropy of stratified polyvinyl chloride

The mechanical anisotropy of a material obtained by stratification of oriented polyvinyl chloride (PVC) layers in different ways has been studied. PVC layers, uniaxially oriented by drawing each with a different draw ratio, were stratified in such a way that their draw axes were either parallel or perpendicular. The propagation velocities of ultrasonic pulses were measured in three principal planes defined by draw axes of the stratified material. With an immersion technique, measurements were performed at 2 MHz and 22°C. Experimentally, it was shown that while stratification of layers with draw axes parallel preserves hexagonal symmetry, the stratified material with layers' draw axes perpendicular possesses orthorhombic symmetry. © 1994 John Wiley & Sons, Inc.     

Investigations of the thermal decomposition of polyvinyl chloride by means of gas chromatography

Gas chromatographic analysis was performed on the products of thermal decomposition of polyvinyl chloride with particular attention on the identification of the obtained reaction products and the role of oxygen in the process.     

Sulfonated polyvinyl chloride fibers for cation-exchange microextraction

Polyvinyl chloride (PVC) fiber was derivatized by concentrated sulfuric acid to yield sulfonated PVC (PVC-SO₃H). The PVC-SO₃H fiber had dual properties as a sorbent, based on cation-exchange and hydrophobicity. In the present study, the novel fiber was used directly as an individual device for extraction purposes in the cation-exchange microextraction of anaesthetics, followed by high-performance liquid chromatography-UV analysis. The results demonstrated that this PVC-SO₃H fiber-based microextraction afforded convenient operation and cost-effective application to basic analytes. The limits of detection for four anaesthetics ranged from 1.2 to 6.0 ng/mL. No carryover (because of its disposable usage), and no loss of sorbent phase (which normally occurs in stir-bar sorptive extraction) during extraction were observed.     

Dyed polyvinyl chloride films for use as high-dose routine dosimeters in radiation processing

Characteristics of the polyvinyl chloride (PVC) films containing 0.11 wt% of malachite green oxalate or 6GX-setoglausine and about 100 μm in thickness were studied for use as routine dosimeters in radiation processing. These films show basically color bleaching under irradiation with ⁶⁰Co γ-rays in a dose range of 5–50 kGy. The sensitivity of the dosimeters and the linearity of dose-response curves are improved by adding 2.5% of chloral hydrate [CCl₃CH(OH)₂] and 0.15% hydroquinone [HOC₆H₄OH]. These additions extend the minimum dose limit to 1 kGy covering dosimetry requirements of the quality assurance in radiation processing of food and healthcare products. The dose responses of both dyed PVC films at irradiation temperatures from 20°C to 35°C are constant relative to those at 25°C, and the temperature coefficients for irradiation temperatures from 35°C to 55°C were estimated to be (0.43±0.01)%/°C. The dosimeter characteristics are stable within 1% at 25°C before and 60 days after the end of irradiation.     

聚氯乙烯用增塑剂的研究新进展

聚氯乙烯(Polyvinyl Chloride,PVC)是世界上用量最大的通用塑料之一,具有优异的综合性能,但其脆性较高,生产加工困难,需要加入增塑剂来提高其柔性.本文概述了PVC常用增塑剂的研究进展,并对其发展方向进行了展望.     

Miniemulsion polymerization of styrene with liquid polybutadiene as the sole co-stabilizer

A low-molecular-weight liquid polybutadiene (LPB) is employed as the sole co-stabilizer in miniemulsion polymerization of styrene in present work. Results indicate that the LPB can be used as an effective co-stabilizer to retard the diffusional degradation of monomer droplets in miniemulsion system and get stable miniemulsions. When the miniemulsions were initiated, particle formation occurred predominantly by monomer droplet nucleation. Moreover, the effects of various reaction parameters on the polymerization kinetics and the nucleation mechanisms were also investigated. These parameters include the level of LPB ([LPB]) and the concentrations of SDS ([SDS]) and potassium persulfate ([KPS]). It is shown that the polymerization rate indicates little dependence on [LPB], while increases with increasing [SDS] and [KPS]. Competition between droplet nucleation and homogeneous nucleation occur in the course of polymerization, but droplet nucleation becomes more important by increasing [LPB] or decreasing [SDS]. Furthermore, the result that the particle size is rather insensitive to changes in [KPS] provides the most compelling evidence for the dominant droplet nucleation.     

The electrophoretic deposition of polyvinyl chloride organosol from organic medium

The results of the studies on the influence of PVC organodispersions properties on the gram-equivalent (Q) of organosol electrophoretically deposited on the electrode have been presented in this work. The influence of the electrical conductivity and organosol concentration on electrophoresis have been determined. The mechanism of organosol particle-potential formation with respect to swelling processes and dispersive agent adsorption have been pointed out.