Multiphase PVC/styrenic copolymer alloys: Internally reinforced by partial miscibility

Although polymer/polymer miscibility is considered the exception to the general rule, in polymer thermodynamics specific interactions between active sites on two polymers can be a driving force for polymer/polymer miscibility. Both the intermolecular interactions of the alpha hydrogen of PVC with carbonyl groups in various polyesters and the polarity of the chlorine bond have been claimed to promote miscibility. Both of these interactions are potential in PVC/styrene maleic anhydride (SMAnh) polymer blends. These specific interactions promoting miscibility and the resulting mechanical properties of these systems is the subject of this report. SMAnh (12.5% MA) copolymer was melt compounded with a stabilized PVC compound using a Haake Rheocord twin screw extruder. Test data generated for these blends were analyzed for miscibility and effects of SMAnh copolymers on heat resistance, fire retardance, impact strength, and processability of PVC.     

On the application of fourier transform infrared spectroscopy to the elucidation of specific interactions in miscible polyester-poly(vinyl chloride) blends

FT-IR spectroscopic studies have been performed in an attempt to elucidate the nature of the specific interactions occurring in miscible poly(?-caprolactone) (PCL)-poly (vinyl chloride) (PVC) blends. Studies of low molecular weight analogues, polymer/solvent mixtures and blends of PCL and α-deuterated PVC are presented. The results strongly suggest that a hydrogen bonding type of interaction between the carbonyl bond of PCL and the α-hydrogen of PVC exists in compatible PCL-PVC blends.     

Fourier transform infrared studies of poly(vinyl chloride) blends with ethylene Co- and terpolymers

The miscibility of poly(vinyl chloride) (PVC) with various ethylene copolymers and terpolymers were investigated using FT-IR spectroscopy. All blends reported were 50/50 by weight. In blends of PVC with ethylene/dimethyl acrylamide copolymer (E/DMA), frequency shifts were observed in the amide carbonyl (proton acceptor) and the α-hydrogen of PVC (proton donor) characteristic bands. In blends of PVC with ethylene/ethyl acrylate/carbon monoxide terpolymer (E/EA/CO), both the ester carbonyl and the ketone carbonyl characteristic frequencies showed mutual shifts and appeared as if they merged together. Small frequency shifts were also observed in the α-hydrogen of PVC characteristic bands. In blends of PVC with ethylene/vinyl acetate/carbon monoxide terpolymer (E/VA/CO), the ester carbonyl frequency showed a shift while that of the ketone carbonyl was essentially unchanged. On the other hand, in PVC blends with ethylene/vinyl acetate copolymer (E/VA), the ester CO frequency did not show any shift, which is consistent with their observed immiscibility. Thus, it is clear that incorporating a ketone ? C?O in ethylene/ester copolymers to form the corresponding terpolymers enhances their miscibility with PVC as earlier proposed on the basis of dynamic mechanical studies. Similar results were shown for blends of PVC with ethylene/2 ethyl hexyl acrylate/carbon monoxide terpolymer (E/2EHA/CO). Frequency shifts imply specific interactions which suggest polymer-polyer miscibility on a molecular scale.     

A study of aromatic polyester/chlorinated polymer blends

A large number of studies have been devoted in recent years to the miscibility behavior of linear polyesters with chlorinated polymers, including poly(vinyl chloride) (PVC), chlorinated PVC, chlorinated poly(ethylenes), and copolymers of vinylidene chloride (Saran). However, similar studies with aromatic polyesters are lacking. It is the purpose of this paper to compare the properties of blends made of poly(ethylene terephthalate), poly(butylene terephthalate) or poly(hexamethylene terephthalate) and of various chlorinated polymers. It is shown that a high concentration of chlorine atoms is required to achieve miscibility. Moreover, there is a “miscibility window” in terms of the carbonyl concentration of polyesters, immiscibility being found for carbonyl concentrations outside this window, A similar behavior was observed before for linear polyester/chlorinated polymer blends and for polyester/polycarbonate blends. Solid state small-angle light scattering experiments were also conducted to follow the morphology of the blends as a function of composition. Spherulites were found but their size vary with composition.     

Dopant macroinitiator for electropolymerisation and functionalisation of conducting polymer thin films

Grafting of polymer brushes from conducting polymer (CP) thin films by controlled radical polymerisation provides a versatile route for the synthesis of functional, electroactive surfaces, with applications in diverse fields. However, one of the drawbacks of this approach is the difficulty of upscaling the synthesis due to the need for specialised CP precursor monomers functionalised with initiation sites. We herein describe an alternative approach to the synthesis of CP‐based polymer brushes whereby atom transfer radical polymerisation initiation sites are attached to a macrodopant incorporated into CP films during electropolymerisation. The facile electropolymerisation of commonly studied CPs with an initiator‐functionalised macrodopant – poly[(styrene sulfonate)‐co‐(2‐bromopropionyloxyethyl methacrylate)] – is demonstrated. The composite polymer films thus synthesised were used as substrates for grafting of hydrophilic polymer brushes. Although poly(styrene sulfonate) is commonly used as a macrodopant in CP films, its initiator‐functionalised derivatives have not previously been utilised in this manner. Despite the elegance of this approach, to the authors' knowledge, there have been no previous examples reported of utilising macromolecular dopants as initiators for subsequent grafting of polymer brushes. © 2017 Society of Chemical Industry     

Miscible polymer blends containing poly(vinyl chloride)

Polymer blends have received particular interest in the past several decades in both industrial and academic research. An initial survey of miscible polymer pairs (1) (1968) revealed 12 combinations. A later survey (2) (1979) noted approximately 180 miscible pairs. Today possibly over 500 miscible combinations have been noted in the open and patent literature (3). However, the vast majority of possible polymer blend combinations are not miscible (thus phase separated). A significant number of diverse polymer structures have been shown to exhibit miscibility with PVC. Several of these blends have been studied in detail and have shown specific interactions primarily involving the α-hydrogen and PVC (considered the proton donor in proton donor-proton acceptor hydrogen bonding type interactions). The blend of poly(?-caprolactone) with PVC illustrates this interaction and has been reported in many published papers. While polymer miscibility in PVC blends offers significant academic interest, industrial utility is also of considerable importance. The addition of low T_g, miscible polymers to PVC offers permanent plasticization. The addition of high T_g, miscible polymers to PVC yields the desired heat distortion temperature enhancement of rigid PVC. A specific example of permanent plasticization involves nitrile rubber blends which have been commercial since the early 1940's. This presentation will review the growing number of polymers noted to be miscible with PVC. The importance of specific interactions will be discussed.     

Different photodegradation processes of PVC with different average degrees of polymerization

The influence of ultraviolet (UV)‐irradiation on the photodegradation mechanism of different average degrees of polymerization (DP ) of poly(vinyl) chloride (PVC) with UV‐irradiation time was investigated by viscosity‐average molecular weight determination, UV‐vis spectroscopy, Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), contact angle measurement, and scanning electron microscopy (SEM). PVC films with different DP (800, 1000, 1300, 3000) were prepared by solution casting. It was carried out exposing specimens to a xenon‐arc light source with a spectral irradiance of 0.68 W/(m² ·nm) at 63°C. It was found that the photodegradation mechanism of the lower DP of PVC (DP = 1000) was different from the higher DP of PVC (DP = 3000). This was because the lower DP of PVC was a homopolymer, while the higher DP of PVC was often produced by copolymerizing with a certain quantity of crosslinking agent (e.g., DAP and DAM). UV‐vis and FTIR spectroscopy studies provided some results concerning the structure of the irradiated PVC, and the carbonyl index and C? Cl index were induced to study the process of PVC photodegradation with different DP . TGA showed that the degradation temperatures of different weight loss increased with the irradiation time. The surface morphology of the irradiated polymer films with different DP was observed by contact angle measurement and SEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of marked poly(vinyl chloride) by reactive processing for identification by UV devices (recycling)

The grafting of sodium 2-thionaphtholate (NaTN) and sodium p-thiocresolate (NaTC) in poly(vinyl chloride) (PVC) has been studied in the melt with the aim of obtaining a marked polymer for easy recognition and separation by UV devices. The influence of reactant concentration. DOP concentration, and temperature was investigated to determine the best conditions to obtain a controlled modification in the polymer. High degrees of grafting, efficiencies > 80%, and no side reactions, such as degradation or crosslinking, have been obtained under polymer processing conditions. The reaction of PVC with both reactants is also stereospecific. The ultraviolet spectrum of p-thiocresolate grafted PVC shows a maximum absorption in the region < 300 nm, and that of a 2% thionaphtholate grafted PVC in the region of 360 nm, which is far from the UV absorption of a plasticized PVC. While the polymer marked with the first reagent can be used without plasticized polymers, the second can also be used with plasticized PVC, and therefore distinguished from polyolefins. The results reported herein may be useful in the development of polymer recycling, although barriers and interferences can exist.     

Borrowing Hydrogen in the Activation of Alcohols

Alcohols can be temporarily converted into carbonyl compounds by the metal‐catalysed removal of hydrogen. The carbonyl compounds are reactive in a wider range of transformations than the precursor alcohols and can react in situ to give imines, alkenes, and α‐functionalised carbonyl compounds. The metal catalyst, which had borrowed the hydrogen, then returns it to the transformed carbonyl compound, leading to an overall process in which alcohols can be converted into amines, compounds containing C C bonds and β‐functionalised alcohols.     

Influence of atmospheric pollutants on the natural and artificial aging of rigid poly(vinyl chloride)

The natural aging of rigid poly(vinyl chloride) (PVC) used in building and construction areas has been studied. Bars of PVC exposed in Algiers, where the concentrations of atmospheric pollutants (NO_x, O₃, hydrocarbons) are known, show a small drop in strain at break and stress at break, whereas hardness remains practically constant. Analysis by IR and UV-visible spectroscopy shows the appearance of chemical structures due to polymer degradation (carbonyl groups, hydroperoxide groups, and polyenes) after the first months of exposure at three sites. It seems that O₃ exerted the most deleterious effect, followed by hydrocarbons and then by NO_x. An artificial aging test was carried out to investigate the effect of O₃ on the degradation of PVC, and the results were compared to those from outdoor aging.     

Ultrafiltration membranes obtained by grafting hydrophilic monomers onto poly(vinyl chloride)

The grafting of vinylacetate (VAc) or hydroxyethylmethacrylate (HEMA) onto poly(vinyl chloride) (PVC) has been performed by means of γ-rays or chemical initiators. The grafted polymer so obtained has been separated by selective extraction and submitted to IR spectroscopy in order to check the amount of grafting. The grafting percentage was measured as a function of the grafting conditions. Using the above-mentioned polymer, dissolved again in DMF, asymmetric ultrafiltration membranes have been prepared by the phase inversion technique. The membranes have been tested with Dextran solutions. Their performances have been studied as functions of the grafting amount. The values of rejection and permeating flux demonstrated the effectiveness of the treatment in enhancing the performances of PVC ultrafiltration membranes.     

Free volume microprobe studies on poly(methyl methacrylate)/poly(vinyl chloride) and poly(vinyl chloride)/polystyrene blends

Blends of Poly(methyl methacrylate) (PMMA)/Poly(vinyl chloride) (PVC) and Poly(vinyl chloride) (PVC)/Polystyrene (PS) of different compositions were prepared by solution casting technique. The blends were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Positron Lifetime Spectroscopy. DSC data were found to be inadequate to describe whether PMMA/PVC blends are miscible or not, possibly because of the small gap in their glass transition temperatures. On the other hand, PVC/PS blends were clearly found to be immiscible by DSC. FTIR results for PMMA/PVC indicate the possible interactions between the carbonyl group of PMMA and α‐hydrogen of PVC. Free volume data derived from Positron lifetime measurements showed that the PMMA/PVC blends to be miscible in low PVC concentration domain. For the first time, the authors have evaluated the hydrodynamic interaction parameter α, advocated by Wolf and Schnell, Polymer, 42, 8599 (2001), to take into account the friction between the component molecules using the free volume data. This parameter (α) has a high value (?57) at 10 wt% of PVC, which could be taken to read miscibility for PMMA/PVC blends to be high. In the case of PVC/PS blends, the positron results fully support the DSC data to conclude the blends to be immiscible throughout the range of concentration. As expected, the hydrodynamic interaction parameter α does not show any change throughout the concentration in PVC/PS blends, further supporting the idea that α is another suitable parameter in the miscibility study of polymer blends. POLYM. ENG. SCI., 46:1231–1241, 2006. © 2006 Society of Plastics Engineers     

二元羧酸有机锡对聚氯乙烯的热稳定作用——性能递变规律与机理

用烘箱变色法测试了几种二元羧酸二烷基锡对聚氯乙烯（PVC）的热稳定作用。结果表明,其热稳定性能随分子中羧酸根羰基C原子正电性的增强而提高;如果分子中含有亲双烯结构单元,则其所稳定的PVC试片在最终黑化前呈现较轻的着色;二元羧酸二烷基锡是通过其带正电荷的羧酸根羰基C原子和（或）二烷基锡离子作为亲电中心与PVC发生亲电反应（简称亲电反应机理）对PVC产生热稳定作用;而如果分子中含有亲双烯结构单元,则同时以亲电反应和Diels-Alder反应机理发挥热稳定作用,但前者为主而后者为辅。     

Interpenetrating polymer networks. I. Photopolymerization of multiacrylate systems

The light-induced polymerization of a triacrylate monomer (TMPTA) has been carried out in a polymer matrix to generate a semi-interpenetrating polymer network (IPN). The reaction kinetics was followed by IR spectroscopy for the various polymer binders studied: poly(vinyl chloride) (PVC), poly(methyl methacrylate), polystyrene, and crosslinked polyurethane. Under intense illumination, crosslinking occurred extensively within a fraction of a second, with formation of a hard and highly resistant polymer material. These semi-IPNs were found to be essentially insoluble in the organic solvents, thus indicating that the acrylate network is grafted onto the polymer matrix, probably because of an efficient chain transfer process. The monomer and photoinitiator concentration, as well as the light intensity were shown to have a great influence on both the rate of polymerization and the final degree of conversion. By using an acylphosphine oxide photoinitiator, PVC–;TMPTA blends have been cured within a few minutes in an accelerated QUV-A weatherometer, which emits low-intensity UV radiation similar to sunlight. © 1994 John Wiley & Sons, Inc.     

Spectroscopic studies of ligand exchange reactions in alkyl- and estertin PVC stabilizers

It has long been appreciated that mercaptoester/Cl exchange equilibria in mono- and dialkyltin mercaptoester/chlorides are important in understanding the stabilization of PVC by alkyltin mercaptoesters (1–3). More recently, IR studies have demonstrated the existence of similar equilibria in mixed mono-/dialkyltin systems; it has been suggested that these exchange reactions may be the source of synergism in the mixed mono-/dialkytin mercaptoester stabilizers (4). The ability to study these systems by IR and NMR methods is based upon the phenmenon of carbonyl to Sn coordination in these compounds and its sensitivity to molecular environment, principally the electronegativity of the tin atom. Our previous studies have now been extended to include estertin (β-carboalkoxyethyltin) mercaptoesters and mercaptoester/chlorides. In contrast to the simple alkyltin systems, the position of the respective mercaptoester/Cl exchange equilibria are dominated by carbonyl to Sn coordination from the ester group of the β-carboalkoxyethyl moiety. Based on the same phenomenon of carbonyl to tin coordination, the nature of alkyl- and estertin mercaptoesters containing alkyltin sulfides has been looked at to a very limited extent.     

A Fourier transform infra-red study of the phase behaviour of polymer blends. Ethylene-vinyl acetate copolymer blends with poly(vinyl chloride) and chlorinated polyethylene

Fourier transform infra-red studies of ethylene-vinyl acetate (EVA) blends with poly(vinyl chloride) (PVC) and chlorinated polyethylene (CPE) are presented. Previous studies have demonstrated that these blends are compatible at ambient temperature and exhibit lower critical solution temperatures (LCST) in a range that is readily accessible and below the onset of significant polymer degradation. Infra-red spectra of EVA-PVC and EVA-CPE films cast from solution and recorded at room temperature exhibit the familiar frequency shifts and band broadenings of the carbonyl stretching vibration that are consistent with compatible blend systems. Significantly, at temperatures above the LCST, these spectral features are not observed, which implies phase separation. By monitoring the frequency of the EVA carbonyl stretching vibration in samples of the blends, an estimation of the relative strength of the intermolecular interactions has been obtained as a function of temperature. A non-linear relationship is observed and the temperature at which the relative strength of the intermolecular interaction appears very weak correlates with the LCST. The implications of these results are discussed.     

Photo‐crosslinking of poly[ethene‐stat‐(methacrylic acid)] functionalised with maleimide side groups

BACKGROUND: Photo‐crosslinkable polymers are well known and commercially applied as photoresists. But so far they have not been applied as membrane materials for separation processes. They would offer certain advantages in membrane fabrication over conventional crosslinked polymer materials. Therefore, in this work, a poly[ethene‐stat‐(methacrylic acid)] (PEMAA) which is a potential membrane polymer for different separation problems was functionalised with photo‐crosslinkable maleimide side groups. RESULTS: It has been shown that PEMAA can be used as basic polymer material and a conversion with 3‐hydroxypropylmaleimide is possible in order to obtain a photo‐crosslinkable polymer. Investigation of the crosslinking mechanism was performed using stationary infrared and UV‐visible spectroscopy as well as nanosecond transient spectroscopy absorption measurements of a rotating film. Intense transient absorption of the maleimide‐esterified PEMAA occurs at 250 nm in the film pointing to maleimide anion formation and crosslinking via an ionic dimerisation mechanism. CONCLUSION: It is found that crosslinking reactions can be observed spectroscopically in situ using a maleimide‐functionalised PEMAA. Furthermore, experiments can be performed in the liquid phase (polymer in solution) as well as in the solid phase (polymer film) using a rotating polymer film sample. Maleimide anion formation and crosslinking via an ionic dimerisation mechanism can be investigated by variation of the polymer structure as well as the structure of the maleimide side groups. Copyright © 2009 Society of Chemical Industry     

Miscibility in PVC-polyester blends

Blends of poly(vinyl chloride), PVC, with the polyesters poly(butylene adipate), poly(hexamethylene sebacate), poly(2,2-dimethyl,1,3-propylene succinate) and poly(1,4-cyclohexanedimethanol succinate) were found to exhibit a single, composition dependent glass transition. Thus, these polyesters are miscible with PVC as others have reported for poly(?-caprolactone). However, mixtures of poly(ethylene succinate), poly(ethylene adipate) and poly(ethylene orthophthalate) with PVC were found not to be miscible. Melting point depression has been used to estimate the blend interaction parameter. These results combined with others from the literature suggest that there is an optimum density of ester groups in the polymer chain for achieving maximum interaction with PVC. Too few or too many ester groups result in immiscibility with PVC.     

Functionalised graphene sheets as effective high dielectric constant fillers

A new functionalised graphene sheet (FGS) filled poly(dimethyl)siloxane insulator nanocomposite has been developed with high dielectric constant, making it well suited for applications in flexible electronics. The dielectric permittivity increased tenfold at 10 Hz and 2 wt.% FGS, while preserving low dielectric losses and good mechanical properties. The presence of functional groups on the graphene sheet surface improved the compatibility nanofiller/polymer at the interface, reducing the polarisation process. This study demonstrates that functionalised graphene sheets are ideal nanofillers for the development of new polymer composites with high dielectric constant values.PACS: 78.20.Ci, 72.80.Tm, 62.23.Kn     

Plasticizer compatibility testing: Dynamic mechanical analysis and glass transition temperatures

Plasticizer compatibility with the polymer, which implies that plasticizer and polymer will remain closely associated as the finished polymer product is used, is critically important in determining whether a flexible poly(vinyl chloride) (PVC) product will have an acceptably long service life. However, with traditional test methods, it is often difficult to distinguish degrees of compatibility among relatively compatible ingredients (ingredients that do not dissociate themselves from the polymer in a very short time or under very mild storage conditions). Dynamic mechanical analysis is a commonly used technique for measuring glass transition temperatures, which can be a useful property in comparing additives' compatibilities. Unlike many polymers, flexible PVC shows two glass transition temperatures, one for the polymer segments that show syndiotactic (but noncrystalline) stereochemistry, and one for the polymer segments that show atactic stereochemistry. The glass transition temperature for the atactic segments of flexible PVC provides some information about the plasticizer's compatibility. When the dynamic mechanical analysis temperature sweep for a plasticized PVC compound detects a particularly low glass transition for the atactic polymer segments, this can be an indication that the plasticizer is relatively incompatible with the PVC. J. VINYL ADDIT. TECHNOL., 21:7–11, 2015. © 2014 Society of Plastics Engineers