PVC Chains Research Articles

Preparation of the interfacial enhanced PA/APVC nanofiltration membrane based on the in-situ amination of substrate membrane

In this research, a novel interfacial enhanced thin film composite nanofiltration (TFC NF) membrane with nail-fixed like surface structure and wave line like cross-section structure, good permeability and superior interfacial stability was prepared by interfacial polymerization (IP) on one-step in-situ aminated polyvinyl chloride (APVC) support layer. The effects of amination agent (triethylenetetramine, TETA) content on the support layers and the effects of the support layers with different degrees of amination on the performance of the TFC NF membranes were studied comprehensively. Furthermore, the interfacial bonding strength of the TFC NF membrane was explored by the inverse permeation test. It was concluded from the results that higher TETA content in casting solution led to the APVC membrane to form macroporous surface structure, thinner top skin layer and larger mean pore size. Meanwhile, more TETA molecules were grafted onto the PVC chains through nucleophilic substitution to participate in IP in a synergistic manner. Accordingly, the corresponding TFC NF membrane formed a nail-fixed like surface structure similar to semi-free-standing polyamide (PA) layer and wave line like cross-section structure with thinner and denser active layer. The water flux of the TFC NF membrane prepared with the optimized APVC membrane as the substrate membrane was increased by 395% at 0.6 MPa compared with the TFC NF membrane prepared with PVC membrane as the substrate membrane, while Na2SO4 rejection did not sacrifice and increased by 3.48%, which manifested that unique structure was favorable to speed up the water transmission and effectively conquered the trade-off effect. Moreover, the representative TFC NF membrane prepared with optimized APVC membrane as the substrate membrane with strong covalent bond between support layer and active layer demonstrated superior interfacial stability in the short-term circulating inverse permeation test.

Comparison of glass transition dynamics between fluorophore-labeled and -doped flexible Poly(vinyl chloride) plasticized by ultra-small branched star Poly(ε-caprolactone)

Glass transition dynamics are one of the most important characteristics with regards to governing the properties of polymers. Herein, we prepare pyrene-labeled and pyrene-doped flexible poly(vinyl chloride)s plasticized by ultra-small branched star poly(ε-caprolactone) (L-PVC/USB-SPCL and D-PVC/USB-SPCL, respectively), and observe the changes in their fluorescence intensities with temperature to ascertain the actual glass transition behaviors of the polymer chains. Fluorescence spectroscopy measurements show that the D-PVC/USB-SPCLs have a single Tg, which is comparable to the Tg measured by differential scanning calorimetry (DSC). However, the L-PVC/USB-SPCLs exhibit a broad glass transition from the onset of Tg for the L-PVC/USB-SPCLs to the endset of Tg for the PVC chain itself (i.e., in the absence of USB-SPCL). In addition, the L-PVC/USB-SPCLs show a relatively low nonradiative decay degree compared to the D-PVC/USB-SPCLs. These results indicate that the labeled pyrene moieties along the PVC chains exhibited limited movement due to the cooperative reptation motion of the chains, even when the space for the polymer chain to move sufficiently is created by an increase in the free volume. As the USB-SPCL content increase in the flexible PVC, the fluorescence intensity reduction degrees of the various D- and L-PVC/USB-SPCLs decrease due to the polarity effect of USB-SPCL. However, in the case of the L-PVC/USB-SPCLs, when the USB-SPCL loading reach 40 phr, the fluorescence intensity reduction degree increases once again due to the dominance of the decrease in caging effect, which reveals that the labeled system, in which a fluorescent substance is directly attached to a polymer chain, allows identification of the motion of the polymer chain in a direct and sensitive manner.

In situ suspension polymerization of vinyl chloride/3-(trimethoxysilyl) propyl methacrylate (MPTMS)-intercalated Mg-Al-hydroxide layered double hydroxide: I. Grain properties

Suspension polymerization of vinyl chloride (VCM) was carried out in the presence of particle of both pristine Mg-Al layered double hydroxide (LDH) and LDH intercalated by 3-(trimethoxysilyl) propyl methacrylate (MPTMS-LDH) in a pilot-scale reactor. The experiments were conducted at different concentrations of each type of the particles (0, 1, 3, 5, 7 wt. % of VCM). The pure LDH and MPTMS-intercalated LDHs were used as co-monomer for fabrication of LDH or MPTMS-LDH/PVC nanocomposites; the particles were directly pre-dispersed in monomer phase before dispersing in the continuous aqueous phase and starting the suspension polymerization. The basal spacing obtained from the X-ray powder diffraction (XRD) showed that the reaction between VCM and MPTMS-LDH was effective, with a further intercalation of PVC chains in the interlayer space. The molecular characterization showed that the polydispersity index (PDI) and molecular weight of the poly (vinyl chloride) (PVC) resin do not change in the presence of the pristine LDH. The MPTMS-LDH, however, decrease the molecular weight and increase the PDI of PVC resin. Also, from the morphological point of view, scanning electron microscopy (SEM) showed that PVC grains produced with high particles content had a smoother surface with more regular shape. Moreover the incorporation of nanoparticles in the VCM suspension polymerization, made particles with a narrower size distribution. The LDH results in the formation of smaller primary particles with higher internal porosity whereas, the larger primary particles with lower internal porosity in the presence of modified particles was observed.

Internal plasticization of poly(vinyl chloride) by grafting acrylate copolymers via copper‐mediated atom transfer radical polymerization

AbstractInternal plasticization of poly(vinyl chloride) (PVC) was achieved in one‐step using copper‐mediated atom transfer radical polymerization to graft different ratios of random n‐butyl acrylate and 2–2‐(2‐ethoxyethoxy)ethyl acrylate copolymers from defect sites on the PVC chain. Five graft polymers were made with different ratios of poly(butyl acrylate) (PBA) and poly(2–2‐(2‐ethoxyethoxy)ethyl acrylate) (P2EEA); the glass transition temperatures (Tg) of functionalized PVC polymers range from − 25 to − 50°C. Single Tg values were observed for all polymers, indicating good compatibility between PVC and grafted chains, with no evidence of microphase separation. Plasticization efficiency is higher for polyether P2EEA moieties compared with PBA components. The resultant PVC graft copolymers are thermally more stable compared to unmodified PVC. Increasing the reaction scale from 2 to 14 g produces consistent and reproducible results, suggesting this method could be applicable on an industrial scale.

The use of new pyridine derivatives as effective photostabilizers for poly (vinyl chloride)

This work included synthesis of several new pyridine derivatives by cyclization of compound (3) with appropriate aromatic aldehydes (4-Chloro-3-formylcoumarin, 4-bromobenzaldehyde, 4-chlorobenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde and 4-N,N-dimethylaminobenzaldehyde) in presence of malononitrile and ammonium acetate to obtain pyridine derivatives (5a-e). The new synthesized compounds have been characterized using Melting point, TLC, FT-IR spectroscopy and 1H-NMR. Five new pyridine derivatives have used like inhibitors untill Poly(vinyl chloride) (PVC) photodegradation. The pyridine derivatives have added into PVC onto a concentration from 0.5% through weight. The PVC thinlayers (40µ m thickness) have irradiated onto room temperature through ultraviolet (UV) light into up into 300 h. The changes within PVC thinlayers after irradiation have monitored through Fourier transform infrared spectroscopy, weight lack, while atomic strength microscopy. These alterations have quite remarkable within the empty PVC thinlayers liken into the ones gained when Active substances have uitilized. The pyridine derivatives have prevent the PVC photodegradation during immediate absorption from UV light, interfere through PVC chains, while touching like radical tie up while proton transfer action into stabilize the polymeric compounds.

Preparation of rare earth complexes with curcumin and their stabilization for PVC

La, Nd, Pr, Ce, Eu and Sm complexes with curcumin have been prepared by the reaction of rare earth nitrate with curcumin in alcohol solution. Six complexes have been characterized by FT-IR, 1H NMR, ICP-MS and TG. The results reveal that the structure of complexes is binary complexes, and then the complexes are marked as RE⋅L2. The initial decomposition temperature of RE⋅L2 is above 260°C, much higher than the processing temperature of PVC. These RE⋅L2 are characterized as PVC heat stabilizers for the first time. The effect of RE⋅L2 on the static and dynamic thermal stability of PVC is investigated by Congo red test and torque rheometer. The results show that the static thermal stability time of PVC is higher than 25.1 min, especially that of PVC with Ce⋅L2 is up to 36.3 min. The dynamic thermal stability time of PVC is higher than 15.3 min, especially that of PVC with Nd⋅L2 is up to 22.0 min. The probably thermal stability mechanism of RE⋅L2 for PVC was proposed based on the measurement of FT-IR, Congo red test and torque rheometer. RE⋅L2 could coordinate with Cl and insular or conjugated double bonds on PVC chains. Also, the cross-linked chains through RE⋅L2 might be formed. Consequently, the dehydrochlorination of PVC and oxidative degradation of the insular or conjugated double bonds were relieved.

A lithiated gel polymer electrolyte with superior interfacial performance for safe and long-life lithium metal battery

Rechargeable lithium metal batteries (LMBs) have gained much attention recently. However, the short lifespan and safety issues restrict their commercial applications. Here we report a novel gel polymer electrolyte (GPE) based on lithiated poly(vinyl chloride-r-acrylic acid) (PVCAALi) to realize dendrite-suppressing and long-term stable lithium metal cycling. PVC chains ensure the quick gelation process and high electrolyte uptake, and lithiated PAA segments enable the increase of mechanical strength, acceleration of lithium-ion transmission and improvement of interfacial compatibility. PVCAALi GPE showed much higher mechanical strength compared with other free-standing GPEs in previous works. It displays a superior ionic conductivity of 1.50 mS cm−1 and a high lithium-ion transference number of 0.59 at room temperature. Besides, the lithiated GPE exhibits excellent interfacial compatibility with lithium metal anodes. Lithium symmetrical cells with PVCAALi GPE yield low hysteresis of 50 mV over 1000 h at 1.0 mA cm−2. And the possible mechanism of the lithiated GPE with improved lithium-ion transfer and interfacial property was discussed. Accordingly, both the Li4Ti5O12/Li and lithium-sulfur (Li-S) cells assembled with PVCAALi GPE show outstanding electrochemical performance, retaining high discharge capacities of 133.8 mAh g−1 and 603.8 mAh g−1 over 200 cycles, respectively. This work proves excellent application potential of the highly effective and low-cost PVCAALi GPE in safe and long-life LMBs.

Preventing thermal degradation of PVC insulation by mixtures of cross‐linking agents and antioxidants

ABSTRACTPoly(vinyl chloride) (PVC) is widely used—in spite of HCl formed from it at elevated temperatures. PVC wire and cable insulation has poor thermal stability, causing the plasticizer to separate from the PVC chains and produce an oily residue, lowering the tensile elongation at break and thus increasing brittleness. One uses cross‐linking agents and antioxidants, as well as mixtures of both, to improve the thermal stability of the plasticizer and tensile properties of PVC after thermal exposure. We performed tensile tests, tribological tests, profilometry, scanning electron microscopy (SEM), and water absorption determination before and after thermal exposure at 136 °C for 1 week. After adding the agents, elongation at break increased by 10 to 20% while the wear rate and water absorption were lower than for the control sample. Less voids are seen in the SEM images after adding these two kinds of agents. The thermal resistance of the PVC cable insulation is best enhanced by combinations of cross‐linking agents and antioxidants. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48816.

Facile Synthesis of Di-Mannitol Adipate Ester-Based Zinc Metal Alkoxide as a Bi-Functional Additive for Poly(Vinyl Chloride).

A new di-mannitol adipate ester-based zinc metal alkoxide (DMAE-Zn) was synthesized as a bi-functional poly(vinyl chloride) (PVC) thermal stabilizer for the first time. The materials were characterized with Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterization results confirmed the formation of Zn–O bonds in DMAE-Zn, and confirmed that DMAE-Zn had a high decomposition temperature and a low melting point. The thermal stability of DMAE-Zn on PVC also was tested by a conductivity test, a thermal aging test, and a UV-visible spectroscopy (UV-VIS) test. PVC stabilized by DMAE-Zn had a good initial color and excellent long-term stability. UV-VIS also showed that the conjugated structure in PVC stabilized by DMAE-Zn was almost all of the triene, suggesting that the addition of DMAE-Zn would suppress the formation of conjugated structures above tetraene. The dynamic processing performance of PVC samples tested by torque rheometer indicated that, having a good compatibility with PVC chains in the amorphous regions, DMAE-Zn contributed a good plasticizing effect to PVC. DMAE-Zn thus effectively demonstrates bi-functional roles, e.g., thermal stabilizers and plasticizers to PVC. Furthermore, FT-IR, a HCl absorption capacity test, and a complex ZnCl2 test were also used to verify the thermal stability mechanism of DMAE-Zn for PVC.

The effect of high UV radiation exposure environment on the novel PVC polymers.

Although plastic induces environmental damages, almost the consumption of poly(vinyl chloride) never stops increasing. Therefore, this work abstracted by two parts, first, synthesis of Schiff bases 1-4 compounds through the reaction of amino group with appropriate aromatic aldehyde, reaction of PVC with Schiff bases compounds 1-4 in THF to form a new modified PVC-1, PVC-2, PVC-3, and PVC-4. The structures of Schiff bases 1-4 and the modified PVC-1, PVC-2, PVC-3, and PVC-4 have been characterized by different spectroscopic analyses. Second, the influence of introducing 4-amino-1,2,4-triazole as a pendent groups into PVC chain investigated on photostability rules of tests. The modified polymers photostability investigated by observing indices (ICO, Ipo, and IOH), weight loss, UV and morphological studies, and all results obtained indicated that PVC-1, PVC-2, PVC-3 and PVC-4 gave lower growth rate of ICO, IPO, and IOH through UV exposure time. The photostability are given as PVC-4 < PVC-3 < PVC-2 < PVC-1 from different mechanisms which suggested building on existence of 4-amino-1,2,4-triazole moieties in the polymer chain.

Analysis of PVC Produced With An Environmentally Friendly Additive Exposed to Gamma Radiation

Commercial Poly(vinyl chloride) (PVC) compounds are based on the combination of the polymer and additives that gives the formulation necessary for the end‐use. In medical‐device applications, PVC may be treated by gamma irradiation in sterilization process. As a consequence of ionization during irradiation, PVC chains undergo simultaneously crosslinking and scission effects. Therefore, it is necessary the study of new additives with radiolytic stabilization characteristics. In this study, the vegetable oil extracted from coffee grounds (OCG) was incorporated in PVC resin as an additive to produce PVC films and PVC test specimens. The viscosity measurements showed that OCG is a promising radioprotection at 0.5 wt% concentration. The results of mechanical and thermal properties are also discussed. The aim of this study is to show that it is possible to develop a formulation for processing PVC with radiation resistance and, at the same time, friendly to the environment due to recycle the wastes from coffee industry.

Enhancing the Mechanical and Electrical Properties of Poly(Vinyl Chloride)-Based Conductive Nanocomposites by Zinc Oxide Nanorods

A simple approach to decorate multi-walled carbon nanotube (MWCNT)–reduced graphene oxide (RGO) hybrid nanoparticles with zinc oxide (ZnO) nanorods is developed to improve the electrical and mechanical properties of poly(vinyl chloride) (PVC)/MWCNT–RGO composites. The ZnO nanorods act as “joint” in three-dimensional (3D) MWCNT–RGO networks and the hybrid particles strongly interact with PVC chains via p-π stacking, hydrogen bonds, and electrostatic interactions, which we confirmed by scanning electron microscopy (SEM) and Raman analysis. By introducing the ZnO nanorods, the RGO–ZnO–MWCNT hybrid particles increased 160% in capacitance compared with MWCNT–RGO hybrids. Moreover, the addition of RGO–ZnO–MWCNT to PVC resulted in the mechanical properties of PVC being enhanced by 30.8% for tensile strength and 60.9% for Young’s modulus at the loadings of 2.0 weight percent (wt.%) and 1.0 wt.%, respectively. Meanwhile, the electrical conductivity of PVC increased by 11 orders of magnitude, from 1 × 10−15 S/m to 1 × 10−4 S/m for MWCNT–ZnO–RGO loading at 5.0 wt.%.

Cardanol Groups Grafted on Poly(vinyl chloride)-Synthesis, Performance and Plasticization Mechanism.

Internally plasticized poly(vinyl chloride) (PVC) materials are investigated via grafting of propargyl ether cardanol (PEC). The chemical structure of the materials was studied by FT-IR and 1H NMR. The performace of the obtained internally plasticized PVC materials was also investigated with TGA, DSC and leaching tests. The results showed that grafting of propargyl ether cardanol (PEC) on PVC increased the free volume and distance of PVC chains, which efficiently decreased the glass transition temperature (Tg). No migration was found in the leaching tests for internally plasticized PVC films compared with plasticized PVC materials with commercial plasticizer dioctyl phthalate (DOP). The internal plasticization mechanism was also disscussed according to lubrication theory and free volume theory. This work provides a meaningful strategy for designing no-migration PVC materials by introducing cardanol groups as branched chains.

Polyphosphates as Inhibitors for Poly(vinyl Chloride) Photodegradation.

Three polyphosphates were used as inhibitors for poly(vinyl chloride) (PVC) photodegradation. The polyphosphates were added to PVC at a concentration of 0.5% by weight. The PVC films (40 µm thickness) were irradiated at room temperature with ultraviolet (UV) light for up to 300 h. The changes in PVC films after irradiation were monitored by Fourier transform infrared spectroscopy, weight loss, viscosity-average molecular weight determination, and atomic force microscopy. These changes were very noticeable in the blank PVC films compared to the ones obtained when additives were used. The polyphosphates can inhibit the PVC photodegradation through direct absorption of UV light, interactions with PVC chains, and acting as radical scavengers.

Plasticized PVC graphene nanocomposites: Morphology, mechanical, and dynamic mechanical properties

Improving the properties of polyvinyl chloride matrix by the incorporation of carbonaceous filler by melt mixing is an unusual thought in the polymer research. Here we incorporated reduced graphene oxide (RGO) as a filler into plasticized polyvinyl chloride (PPVC) matrix by melt mixing, an eco‐friendly method. The effect of addition of filler in the morphology of the PPVC nanocomposites was analyzed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and Raman spectroscopy. The mechanical response of the nanocomposites to an applied stress was studied. A 50% improvement in mechanical properties was obtained at a low filler loading. A decrease in elongation was observed at higher RGO loading. The dynamic mechanical analysis (DMA) of the nanocomposites indicated an increase in glass transition temperature of the PVC up on the addition of RGO. This has confirmed the confinement of PVC chains at the graphene surface. As a result, the storage modulus of the nanocomposites showed an increase up on the addition of the nanofiller. Theoretical values of the storage modulus were calculated using various theoretical equations. The effectiveness of filler on the storage modulus is estimated and is found to be consistent with the results obtained experimentally. POLYM. ENG. SCI., 58:E104–E113, 2018. © 2017 Society of Plastics Engineers

Superiorly Plasticized PVC/PBSA Blends through Crotonic and Acrylic Acid Functionalization of PVC.

Superior plasticization efficiency was achieved by a grafting from functionalization of the PVC backbone. This was deduced to a synergistic effect of internal plasticization and improved intermolecular interactions between PVC and an oligomeric poly(butylene succinate-co-adipate) (PBSA) plasticizer. A mild grafting process for functionalization of the PVC chain by crotonic acid (CA) or acrylic acid (AA) was used. The formation of PVC-g-CA and PVC-g-AA was confirmed by FTIR and 1H NMR. Grafting with the seemingly similar monomers, CA and AA, resulted in different macromolecular structures. AA is easily homopolymerized and long hydrophilic poly(acrylic acid) grafts are formed resulting in branched materials. Crotonic acid does not easily homopolymerize; instead, single crotonic acid units are located along the PVC chain, leading to basically linear PVC chains with pendant crotonic acid groups. The elongation of PVC-g-CA and PVC-g-AA in comparison to pure PVC were greatly increased from 6% to 128% and 167%, respectively, by the grafting reactions. Blending 20% (w/w) PBSA with PVC, PVC-AA or PVC-CA further increased the elongation at break to 150%, 240% and 320%, respectively, clearly showing a significant synergistic effect in the blends with functionalized PVC. This is a clearly promising milestone towards environmentally friendly flexible PVC materials.

Efficiency and mechanism for the stabilizing action of thiouracil derivatives as novel thermal stabilizers for poly(vinyl chloride) and the synergistic effect with calcium stearate

Novel thiouracil thermal stabilizers for rigid poly(vinyl chloride) (PVC), 6-methyl-2-thiouraci (6M2TU), 5-methyl-2-thiouraci (5M2TU), and 6-propyl-2-thiouraci (6P2TU) were synthesized successfully via a precipitation method, and characterized with 1H NMR spectra. Investigation of these thiouracil derivatives as thermal stabilizers for poly(vinyl chloride) (PVC) was measured by thermogravimetric analysis (TGA), congo red test, fourier transform infrared (FTIR), and discoloration test. The results show that the thiouracil derivatives have strong ability to replace the labile chlorine atoms in PVC chains, but weak ability to absorb hydrogen chloride. Moreover, PVC stabilized with these thiouracil derivatives and calcium stearate (CaSt2) exhibit greater stabilizing efficiency compared with traditional Ca/Zn stabilizers with the same concentration.

Continuous dosing of fast initiator during vinyl chloride suspension polymerization: Thermal stability of PVC resin

ABSTRACTThermal stability of poly(vinyl chloride) (PVC) produced using continuous dosages of a fast initiator method was investigated in terms of morphological and microstructural characteristics. The results were compared with the properties of the PVC prepared by conventional polymerization method. The Brabender® Plastograph and DSC results showed a lower fusion time, higher stable time, and greater degree of fusion for PVC obtained by polymerization using initiator continuous dosage method. Also, chemical analysis indicated that the PVC produced under an initiator continuous dosage system have lower structural defects, that is, branch numbers, internal double bonds, labile chlorine, and tacticity index, thereby improving the thermal stability of PVC resin. The results obtained from dehydrochlorination and thermogravimetry analysis confirm the improvement of thermal stability of PVC chains synthesized with continuous dosages of a fast initiator. Moreover, it was found that the concentration of microstructural defects and the dehydrochlorination rates of the PVC samples prepared by both processes increase with monomer conversion, particularly after critical conversion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44480.

Design and structural study of a triple-shape memory PCL/PVC blend

Abstract Poly(e-caprolactone) (PCL) and poly (vinyl chloride) (PVC) are miscible with each other, and their glass transition temperatures differ a lot. With this feature, we tried to design a triple-shape memory material by simply blending them together. After carefully examining the glass transition broadness and the tensile behavior of various PCL/PVC blends, PCL-30% (the weight fraction of PCL was 30%) was picked out as the best candidate. It fulfills two criterions that it has a wide glass transition range and it has no strain or stress induced crystallization. Subsequent triple-shape memory procedure proves that it could function as an effective shape memory blend. The structure was studied by SAXS/WAXS and nano-scale periodic structure was found, which was composed of crystalline and amorphous PCL regions of 4.7 nm and 8.4 nm respectively. Such periodic domains would orient along the stretch direction, but it kept stable and could restore to its original state after the stress was released. Dichromic FTIR discerned the orientation of PCL chains at low temperature and PVC chains at high temperature. It can be concluded that both the nano-scale PCL crystalline structures and physical entanglements served as the fixed phase, while the amorphous PVC and PCL regions played as the reversible phase at high and low switch temperatures respectively.

Pharmaceutical Compounds as Photostabilizers

n this paper, some pharmaceutical compounds were used and their impact on the photostability of polymer poly (vinyl chloride) (PVC) was study. The PVC films containing a variant concentration of compounds 0.25, 0.5, 1% by weight were produced by casting method from tetrahydrofuran (THF) solvent. The photostabilization activities of these compounds were determined by calculating the photodegradation rate constant for photostabilizer (kd). The stabilizing efficiency of pharmaceutical compounds is attributed to the replacement of the labile chlorine atoms on the PVC chains by a relatively more stable moiety of the pharmaceutical stabilizer. The Photostabilization activity of these compounds is determined by weight loss method with irradiation time.