Azelaaldehydic acid ester-acetal derivatives as plasticizers for poly(vinyl chloride)

Certain ester-acetal derivatives of azelaaldehydic acid have been evaluated as a new type of plasticizer of PVC. In gerneral, these compouonds have high compatibility and impart excellent low-temperature, mechanical, heat- and light -stability properties to the plasticized PVC. The 2-ethylihexyl ester bis (2-methoxyethyl) acetal, in particular, appeared to have the best combination of properties for a useful plasticizer. The results indicate that a unique and useful type of plasticizer-stabilizer can be obtained from derivatives of azelaaldehydic acid.     

Diamide derivatives as photostabilizers for plasticized poly(vinyl chloride)

Some diamide derivatives have been prepared, characterized, and investigated as photostabilizers for plasticized poly(vinyl chloride) (PVC), containing dioctyl phthalate and dibutyl phthalate in a concentration of 30% by weight of the polymer. The stabilizing efficiency of the prepared diamides was evaluated by determining the weight loss percentage that resulted from HCl evolution during the photodegradation process. Moreover, the efficiency was evaluated by determining the amount of gel formed as well as the intrinsic viscosity of the soluble fractions of the photodegraded polymer. The extent of discoloration of the photodegraded stabilized and plasticized PVC was also investigated. The stabilization mechanism and the effect of plasticizers on the photostability of PVC are discussed. J. Vinyl Addit. Technol., 2008. © 2008 Society of Plastics Engineers     

Phenyl urea derivatives as organic stabilizers for rigid poly(vinyl chloride) against photo‐degradation

Phenyl urea derivatives have been prepared and investigated as photostabilizers for rigid PVC by measuring the extent of weight loss (%), the amount of gel formation as well as the intrinsic viscosity of the soluble fractions of the degraded polymer. Moreover, the efficiency of these stabilizers was evaluated from the extent of discoloration of the degraded polymer in their presence. The results indicated a reasonable stabilizing effect of these derivatives when compared with the commercially used UV stabilizers: phenyl salicylate (Salol) and methanone, 2‐hydroxy‐4‐(octyloxy)‐phenyl‐benzophenone. A synergistic effect is achieved when the phenyl urea derivatives are mixed with the UV absorbers in the ratio (75 : 25%), respectively. A radical mechanism is proposed to account for the stabilizing action of the products investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2217–2226, 2007     

聚氯乙烯固载聚乙二醇的合成及其催化活性的研究

合成了两种聚氯乙烯固载聚乙二醇相转移催化剂。这类催化剂可用于酚醚、Ｎ－丁基咔唑的合成和苯甲酸乙酯的水解反应中。研究表明，它们的催化活性良好，重复性能满意。     

Synthesis and characterization of a mass polymerized impact modified poly (vinyl chloride) resin

Rigid homopolymer PVC has many uses and has two disadvantages usually compensated for by additives. One difficulty is processability handled by processing aids and the other is an inherent low impact strength increased by impact modifier compounding. This paper describes graft-copolymerized vinyl chloride on rubber-type polyolefins which give better processability and greatly improved impact resistance.     

Preparation and structural characterization of nanocrystalline poly(vinyl chloride)

This article describes the development of novel nanocrystalline poly(vinyl chloride) (PVC) for potential applications in PVC processes and reports improvements in the mechanical properties and thermal resistance. Before the preparation of nanocrystalline PVC via jet milling, PVC was spray‐treated and heat‐treated to improve its crystallinity. The pulverization and degradation, morphology, crystalline structure, and melting‐point changes of postmodified PVC during jet milling and the relationship between the distributions of the particle size and processing temperature were investigated. X‐ray analysis and density testing indicated increased density and improved crystallinity. The crystalline region of nanocrystalline PVC was less than 80 nm, with a particle size distribution of 5–20 μm and a melting point of less than 128°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 563–569, 2004     

梳型接枝PVC的制备

研究了聚氯乙烯与肉豆蔻酸钠的接枝反应,并制备梳形接枝PVC。利用FT-IR、1H-NMR对梳型接枝PVC的结构进行表征,并探讨反应条件对接枝率的影响。结果表明,梳形侧链成功接枝到PVC上,且在反应温度70℃、反应时间9h、单体用量50%时,接枝率最高。     

Diester based on castor oil fatty acid as plasticizer for poly(vinyl chloride)

Castor oil is a renewable resource that has potential uses as an environmental friendly material for a range of applications. In recent years, much efforts have been driven to develop alternate plasticizer for medical and commodity plastics due to growing concerns about dioctyl phthalate (DOP) for flexible poly(vinyl chloride) (PVC). In this study, a bio‐based plasticizer was synthesized by a two‐step esterification reaction of castor oil fatty acid (COFA) with benzyl alcohol and octanoic acid in the presence of catalyst (dibutyl tin dilaurate). The structure of the octanoic ester (OE) was confirmed by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, acid value, and hydroxyl value. OE was used as a coplasticizer in PVC for partial replacement of DOP. The addition of OE exhibited good incorporation and plasticizing performance in the PVC sheets. Incorporation of OE resulted in good plasticizing, tensile strength, percentage elongation, exudation, thermal stability, and chemical resistance because of the presence of long carbon chains of COFA. Differential scanning calorimetry (DSC), thermogravimetric analysis, and color measurements were also performed to evaluate the effect of OE. With the increase in OE, DSC and hardness results showed marginal deviation from those obtained for DOP‐plasticized sheets. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40354.     

Polycaprolactone as a permanent plasticizer for poly(vinyl chloride)

Polycaprolactone at moderate usage levels has been determined to provide desirable modifications of both rigid and plasticized poly(vinyl chloride). In rigid PVC it effected significant improvement in melt processing as well as good modulus, tensile strength, and kerosene resistance. Impact strength was not measurably altered, but heat-distortion temperature was appreciably lowered. In flexible PVC, polycaprolactone contributed increased tensile strength and ultimate elongation, reduced volatility, and kerosene extraction. Lowering of modulus and flex temperatures were similar to conventional liquid polymeric plasticizers, but melt processability was not as good as lower-molecular-weight plasticizers.     

Improving the antifouling property of poly(vinyl chloride) membranes by poly(vinyl chloride)‐g‐poly(methacrylic acid) as the additive

To improve the antifouling property of poly(vinyl chloride) (PVC) membranes, a series of poly(methacrylic acid) grafted PVC copolymers (PVC‐g‐PMAA) with different grafting degree were synthesized via one‐step atom transfer radical polymerization process utilizing the labile chlorines on PVC backbones followed by one‐step hydrolysis reaction. PVC/PVC‐g‐PMAA blend membranes with different grafting degree and copolymer content were prepared by nonsolvent induced phase separation method. The surface chemical composition, surface charge, membrane structures, wettability, permeability, separation performances and the fouling resistance of blend membranes were carefully investigated. The results indicated that the PMAA chains were segregated towards the surface and the membranes were endowed with negative charge. The hydrophilicity and permeability of the blend membranes were obviously improved. Furthermore, the antifouling ability especially at neutral or alkaline environments was also significantly increased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42745.     

Graft copolymerzation of poly(vinyl chloride) with styrene. I. Synthesis and characterization

Graft copolymerization of poly(vinyl chloride) (PVC) partially dehydrochlorinated by heating in nitrobenzene was investigated using styrene as monomer and anhydrous AlCl₃ as cationic initiator in the temperature range of 0–35°C. Effect of monomer, catalyst, and PVC concentration on % graft-on was also evaluated. Introduction of labile sites in PVC by partial dehydrochlorination in nitrobenzene resulted in an increase in % graft-on. Intrinsic viscosity of PVC–g–polystyrene in THF initially increased with an increase in % graft-on. At higher % graft-on a decrease in [η] was observed.     

Novel poly(vinyl alcohol)-g-poly(hydroxy acid) copolymers: Synthesis and characterization

Poly(vinyl alcohol) (PVA) was reacted with three hydroxy acids (HA), namely D,L-lactic acid (LA), glycolic acid (GA) and D,L-3-hydroxybutyric acid (HB). The graft copolymers obtained were thoroughly characterized by ¹H and ¹³C NMR, FTIR, and DSC. Copolymer compositions were in the range 14–45 mol% HA with average lateral chain lengths in the range 1.1–1.3. The CO stretching band, arising from the lateral polyester chains, presents significant differences from that of pure polyesters. In case of the VALA and VAGA copolymers, carbonyl groups are almost completely interassociated with hydroxyl groups and as a result the carbonyl band presents a single contribution; however, splitting appears in VAHB. The band at about 1735 cm^?1 already observed for Poly(3-hydroxybutyrate) P3HB was reexamined in the light of molecular models for VAHB and the splitting observed was attributed to C–H???OC and to O–H???OC hydrogen bonding. The thermal analysis of copolymers demonstrates that esterification suppresses crystallinity and increases free volume, both accounting for a Tg reduction with regard to PVA. The stronger intermolecular hydrogen bonding interactions found in PVA with the chemically modified PVAs opens an interesting way towards miscibility with polyesters and other polymer systems containing carbonyl groups.     

Synthesis and characterization of poly(vinyl acetate peroxide)

Poly(vinyl acetate peroxide) (PVACP) was prepared from vinyl acetate by free-radicalinitiated oxidative polymerization. The polyperoxide was isolated and characterized by different spectroscopic methods. The extreme instability of PVACP was demonstrated by FTIR spectroscopy. The ¹H-and ¹³C-NMR studies show the irregularities in the polyperoxide chain due to the cleavage reactions of the propagating peroxide radical. Thermal degradation studies using differential scanning calorimetry revealed that PVACP degrades at a lower temperature and the heat of degradation is in the same range as reported for other vinyl polyperoxides. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of poly(vinyl alcohol) carbonate

Poly(vinyl alcohol) (PVA) was reacted with dimethyl carbonate (DMC) to prepare PVA carbonate (PVAC), which is considered to have three structures, cyclic carbonate (I), monocarbonate (II) and crosslinking carbonate (III). Though the reaction proceeded easily in dimethyl sulfoxide at 120 °C without any catalyst, the yield of the ethanol‐insoluble part of the products was less than that with the reaction containing a catalyst such as tetrabutylammonium bromide (TBAB). TBAB concentration did not affect the rate of carbonic esterification but affected the yield of the ethanol‐insoluble part. The rate of carbonic esterification increased with an increase in reaction temperature, and the activation energy of this reaction was 114 kJ mol⁻¹. Carbonic esterification under reduced pressure showed a larger degree of esterification than that of the reaction under atmospheric pressure. PVAC was soluble in water at a low degree of carbonic esterification (DC) but became insoluble as DC increased. The thermal property of PVA reduced by the carbonic esterification was improved as DC increased. © 2000 Society of Chemical Industry     

The solubility of vinyl chloride in poly(vinyl chloride)

The solubility of vinyl chloride monomer (VCM) in PVC powders has been studied by equilibrium vapor pressure and microbalance gravimetric techniques at temperatures from 30 to 110°C. At temperatures and VCM concentrations above the glass transition, the solubility closely follows the Flory-Huggins equation with χ = 0.98 and is independent of temperature and of the PVC type, molecular weight, or history. In the glassy state, the VCM solubility is higher than the Flory-Huggins value and shows pronounced dependence upon time and the PVC history. These results have been interpreted through the dual-mode sorption concept of Michaels, Vieth, and Barrie: Normal dissolution follows the Flory-Huggins relation, and the additional glassy-state solubility represents the contribution of a hole-filling process. Changes in solubility with time and sample history parallel well-known volume relaxation processes, indicating that vapor solubility measurements offer a direct and sensitive measure of the free-volume state of glassy polymers.     

Preparation and characterization of flexible poly(vinyl chloride) foam films

In this study, the effect of activator ZnO and heating time at 190°C on foaming, gelation, and dehydrochlorination of poly(vinyl chloride) (PVC) plastisol was investigated. For this purpose, a PVC plastisol was prepared by mixing PVC, dioctyl phthalate (DOP), azodicarbonamide (ADC), ZnO, and the heat stabilizers calcium stearate (CaSt₂) and zinc stearate(ZnSt₂). PVC plastisol films were heated for 3, 6, 12, and 24 min periods at 190°C to see the effect of heating time on the gelation and foaming processes of the PVC foam. The time of 12 min was determined to be optimum for the completion of gelation and foaming processes without thermal degradation of PVC. No foaming was observed under the same conditions for the samples without ZnO. ZnO had a significant catalytic effect on ADC decomposition, accelerating the foaming of the films. Average porosity measurement showed a consistent increase in porosity with heating time up to 76% and the average density decreased from 1.17 to 0.29 g/cm³ on foaming. Tensile tests showed that the tensile strength and tensile strain both increased considerably up to 0.98 MPa and 207%, respectively, with heating time and the elastic modulus was seen to gradually decrease from 4.7 to 0.7 MPa with heating time. Films without ZnO had higher tensile strength since there were no pores. PVC thermomat tests showed that ZnO lowered the stability time of plastigel film with azodicarbonamide. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of ionomeric poly(vinyl butyral)

A route to synthesizing novel poly(vinyl butyral) ionomers (IPVB), via a condensation polymerization process, has been developed. In the process, ionic groups were permanently incorporated into the poly(vinyl butyral) backbone by using an ion-containing aldehyde in addition to butyraldehyde during the acetalization of poly(vinyl alcohol). The resulting polymers demonstrated properties typical of ionomer systems, i.e., they behaved as “thermally reversible crosslinked thermoplastics” due to the presence of ionic associations present in the polymers. The ionic associations enabled the polymers to behave as crosslinked materials at ambient temperatures, whereas, at higher temperatures (processing temperatures), the ionic associations were lost, thus allowing the polymers to flow. Consequently, at ambient temperatures, the IPVBs demonstrated increased stiffness as determined from the storage modulus of the polymers, whereas, at higher temperatures, the IPVBs demonstrated moduli and stress-relaxation properties comparable to those of conventional poly(vinyl butyral). The IPVBs were characterized by a number of techniques including, high resolution NMR spectroscopy (¹H, ¹³C), dilute solution viscometry, dynamic mechanical analysis, and differential scanning calorimetry (DSC). Characterization was done on plasticized and unplasticized IPVBs.     

Benzyl ester of dehydrated castor oil fatty acid as plasticizer for poly(vinyl chloride)

The poly(vinyl chloride) (PVC) industry plays an important role in today's total plastics industry. The major volume of PVC is used as soft and plasticized PVC. PVC applications consume approximately 80% of the total production of plasticizers. Most of the common plasticizers are aromatic esters of phthalic acid. In the majority of countries, phthalate plasticizers are banned due to their carcinogenic properties. The concern raised about toxicity led to a large demand for bio‐based non‐toxic plasticizers. Hence, there is an increasing interest in replacing the phthalate plasticizers with those produced from simple bio‐based materials. Dehydrated castor oil fatty acid (DCOFA) is a renewable resource which can be esterified and used as an environment friendly plasticizer for PVC. Benzyl ester (BE) was prepared by reacting DCOFA with benzyl alcohol in the presence of catalyst at 170–180 °C. Esterification was further confirmed by acid value, hydroxyl number, ¹H NMR and Fourier transform IR spectroscopy. The modified plasticizer was used in various proportions as a co‐plasticizer in PVC for partial replacement of dioctyl phthalate (DOP). With an increase in the proportion of BE in PVC samples, a good plasticizing performance was observed. The incorporation of BE also resulted in a reduction in viscosity and viscosity pick‐up and improved mechanical, exudation, thermal degradation and chemical resistance properties. The presence of BE showed a reduction in the whiteness index due to presence of conjugated double bonds in the structure. The results of DSC, XRD and Shore hardness studies showed no significant variation in properties compared with those of DOP‐plasticized sheets and thus we can conclude that BE can be used as a co‐plasticizer in PVC. © 2013 Society of Chemical Industry