Thermal Stability Of Polyvinyl Chloride Research Articles

Using solid waste from the leather tanning industry to produce a mixed calcium/zinc thermal stabilizer for polyvinyl chloride

The leather tanning industry has historically posed considerable environmental challenges owing to the substantial solid waste it produces. This study examines innovative uses for the solid waste generated by this sector, focusing on the waste from the fleshing process. Our research involved extracting fat from fleshing waste, synthesizing Ca and Zn carboxylates from the extracted fat, and assessing their effectiveness as a combined Ca/Zn thermal stabilizer for polyvinyl chloride (PVC). The synthesized Ca and Zn carboxylates contained 6.4% Ca and 11.4% Zn, respectively, while the total fatty matter was determined to be 86.2% and 88.5%, respectively. Thermal analysis indicated that both carboxylates remained stable up to 200 °C. Tests on dehydrochlorination and roll milling revealed that the mixed Ca/Zn thermal stabilizer effectively improved the thermal stability of PVC resin. It also showed a synergistic effect when combined with pentaerythritol, enhancing its overall efficacy. The synthesized mixed Ca/Zn thermal stabilizer exhibited thermal stabilizing properties and flowability comparable to those of mixed Ca/Zn stearate, a widely used thermal stabilizer for PVC. These results suggest that fleshing fat could serve as a valuable raw material in the production of mixed Ca/Zn-based PVC thermal stabilizers.

Valorization of palm oil refining by-product for organotin mercaptide as a polyvinyl chloride thermal stabilizer: Synthesis, efficacy and comparison to mixed metal stearate

Organotin mercaptide-based thermal stabilizer is recognized for its effectiveness in enhancing thermal stability of polyvinyl chloride (PVC). In this study, we synthesized an organotin mercaptide-based thermal stabilizer from palm fatty acid distillate, which is a by-product of palm oil refining process, and then evaluated its thermal stabilizing effects on PVC and compared its efficacy and economics to those of mixed metal stearate. The synthesized thermal stabilizer manifests as methyltin mercaptoethyl carboxylate sulfides. Both dehydrochlorination and two-roll mill discoloration tests have demonstrated the high efficacy of the resulting thermal stabilizer in stabilizing PVC, surpassing the performance of mixed metal stearate, as evidenced by the lower dosage required. The synthesized PVC thermal stabilizer not only provides effective stabilization but also presents a competitive viable alternative.

Amorphization Activates Biocompatible MgAl‐Layered Double Hydroxide for Efficient Multiple Free Radical Scavenging

AbstractThe exploitation of effective and nontoxic materials with antioxidant activity to mitigate or inhibit the damage caused by elevated levels of free radicals has attracted considerable attention across diverse fields. Herein, this study demonstrates that a biocompatible MgAl‐layered double hydroxide (LDH) can be activated for multiple types of free radical scavenging with unexpected activity through amorphization (a‐MgAl‐LDH). Detailed characterization reveals that numerous oxygen defects are introduced after amorphization. Mechanistic studies and theoretical simulations indicate that amorphization‐induced oxygen defects in a‐MgAl‐LDH promote radical adsorption and reduce the reaction energy barriers, thereby resulting in enhanced radical scavenging activities. Consequently, a‐MgAl‐LDH demonstrated remarkable efficiency in mitigating the oxidative injury induced by Rosup in cells and provided thermal stabilization of polyvinyl chloride against degradation. This study demonstrates the transformation of inert MgAl‐LDH into a promising, nontoxic, and cost‐effective nano‐antioxidant option for antioxidative therapy or polymer stabilization and highlights the significance of crystallinity engineering of nanomaterials for efficient free radical scavenging.

Solid phase synthesis of alkoxyl tin and the role of alkyl for Multi-stage thermal decomposition of polyvinyl chloride

To prepare an innovative thermal stabilizer for polyvinyl chloride (PVC), the micro-nano powders of alkoxyl tin (RxOSn) were synthesized via a solid phase reaction at room temperature, using the surfactant sodium benzene sulfonate (SBS) as a catalyst. Theoretical calculation of deprotonation reaction energy of monobasic alcohol and tin chloride was performed with the framework of DFT, and their structures were characterized by XRD, SEM, FT-IR, XPS, and its surface wetting performance was carried out by contact angle (CA). Meanwhile, the multi-stage thermal stability of PVC with 10% RxOSn sample, and the role of alkyl groups (Rx, x = 2 ∼ 5) in the RxOSn/PVC were investigated. The results show that the RxOSn samples exhibit a microstructure akin to the rutile of SnO2. Multi-stage kinetic studies of exothermic reactions has confirmed that the alkoxyl wetting performance of stabilizers becomes a determining factor, while the variation in activation energy (Ea) values seems to be mainly influenced by the Rx alkyl groups in the RxOSn samples. Besides, the differences in the lattice parameter a of RxOSn were validated to have a certain impact on the stabilizing effect of PVC, and the Ea of PVC degradation is closely related to the relative value of exposed crystal surfaces (D(110)/D(101)). This series of materials is easily synthesized and can effectively enhance the thermal stability of PVC, offering a wide range of potential applications.

Investigation of thermal and mechanical properties of new nitrogen-rich organic based heat stabilizers for poly (vinyl chloride)

Urea cyanurate, as a new nitrogen-rich organic-based heat stabilizer, for the enhancement to thermal properties of polyvinyl chloride (PVC) is prepared via the simple precipitation method, in this study. Characterization, thermal and mechanical properties of the stabilized PVC were examined by means of fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA/DTG), X-ray photoelectron spectroscopy (XPS) measurements, discoloration test, congo red test and the weight-loss method, thermal aging test, and tensile analysis. Results showed that the thermal stability of PVC is improved after the addition of urea cyanurate in PVC formulation and weight loss related to HCl releasing in the normal PVC processing temperature (180°C) is less than 1%. Enhancement of the thermal properties and stability time of the PVC lead to decreased degradation tendency. Oven-aging test result showed that the color change during degradation process of PVC samples improved by adding the urea cyanurate. The tensile strength of stabilized samples were about 42%, higher as compared to the pure PVC. The optimum and best results for improving the thermal and mechanical properties of PVC were obtained by incorporating the 3 wt % of the urea cyanurate.

Preparing epoxidized vegetable oil from waste generated by the kapok fiber industry and assessing its thermal stabilization effect as a co-stabilizer for polyvinyl chloride

This paper describes the epoxidation of vegetable oil derived from waste kapok seeds using performic acid, which was generated in situ with sulfuric acid acting as a catalyst. The mole ratio of formic acid to double bonds varied between 0.25 and 1.00. The completion of the reaction has been verified by analyzing FTIR and NMR spectra. The resulting epoxidized kapok seed oil (EKSO) has a maximum oxirane oxygen content of 2.7%, achieved at a formic acid to double bond mole ratio of 0.5. The study has also examined the potential use of EKSO as a co-stabilizer in the presence of Ca/Zn stearate for stabilizing polyvinyl chloride (PVC). Both static and dynamic tests demonstrated that incorporating EKSO into the Ca/Zn stearate system leads to a significant increase in the thermal stability of PVC. Moreover, the effectiveness of EKSO as a co-stabilizer was found to be comparable to that of epoxidized soybean oil (ESBO). However, the use of EKSO did result in a decrease in the strength of PVC due to an increase in plasticity, although this effect was minimal at low dosages and was also observed with ESBO. On the other hand, when utilizing small doses (<2 phr), there is a tendency for flowability to decrease, but the reduction is not significant either. Overall, these findings suggest that EKSO could be a valuable co-stabilizer for PVC in industrial applications, as it enhances PVC's thermal stability without significantly compromising its mechanical and flow properties.

Effect of different tin neodecanoate and calcium–zinc heat stabilizers on the thermal stability of PVC

Abstract Heat stabilizers are crucial additives for enhancing the thermal stability of polyvinyl chloride (PVC) during processing. Among the various heat stabilizers available, organic tin compounds have shown remarkable effectiveness. In this study, we investigated the use of dimethyltin dineodecanoate (DMTDN), dibutyltin dineodecanoate (DBTDN), and dioctyltin dineodecanoate (DOTDN) as heat stabilizers for PVC. These compounds were combined with calcium stearate (CaSt2) and zinc stearate (ZnSt2) to improve the thermal stability of PVC materials. The results demonstrated that the thermal stabilization effects of the three tin neodecanoates, when used as standalone heat stabilizers, followed the order: DOTDN &gt; DBTDN &gt; DMTDN. Notably, the thermal stability and lubricity of the three-component heat stabilizer (MTN5-C4Z1, BTN5-C4Z1, and OTN5-C4Z1, respectively), which consisted of the three types of tin neodecanoate, CaSt2, and ZnSt2 in a ratio of 5:4:1, outperformed the use of tin neodecanoate alone. This study offered potential formulations to reduce the application cost of tin neodecanoate as a PVC heat stabilizer.

Preparation of rare-earth terephthalic acid stabilizer and its effect on thermal stability of polyvinyl chloride

Preparation of rare-earth terephthalic acid stabilizer and its effect on thermal stability of polyvinyl chloride

A new organic zinc thermal stabilizer containing two kinds of anions with excellent thermal stability on polyvinyl chloride by multistep substitution

AbstractA new kind of highly efficient organic zinc thermal stabilizer for polyvinyl chloride (PVC), zinc arginine stearate [Zn(Arg)(St)], is designed by introducing the arginine and stearate to the same zinc atoms to regulate the binding energy between anions and cation. Gaussian soft is used to calculate the binding energy. The results of Fourier transform infrared spectra, elemental analysis, thermogravimetric analysis, and differential scanning calorimetry show that Zn(Arg)(St) has been successfully synthesized. Zn(Arg)(St) stabilized PVC displays excellent Congo red, static and dynamic thermal stability time, especially the excellent initial whiteness and whiteness retention time. The thermal stability mechanism of Zn(Arg)(St) attributes to the different binding energy between the two anions and zinc cation, which results in Zn(Arg)(St) continuously replacing the unstable chlorine atoms step by step by Arg and St anions. Moreover, the amino group in Arg could complex ZnCl2 to inhibit the “zinc burning” effect, and the guanidine group could absorb HCl to inhibit the “autocatalytic effect” of HCl. In addition, Zn(Arg)(St) has a remarkable lubrication effect, which also enhances the thermal stability of PVC. Thus, Zn(Arg)(St) is an environmentally friendly thermal stabilizer for PVC with an excellent thermal stability effect. Importantly, this work also proposes a new method to design highly efficient thermal stabilizers for PVC.

Enhancing the Initial Whiteness and Long-Term Thermal Stability of Polyvinyl Chloride by Utilizing Layered Double Hydroxides with Low Surface Basicity

This study investigated the impact of surface basicity on the performance of layered double hydroxides (LDHs) as heat stabilizers for polyvinyl chloride (PVC). LDHs with varying surface basicity were synthesized and characterized using XRD, SEM, BET, and CO2-TPD. The LDHs were then combined with zinc stearate and dibenzoylmethane to create an environmentally friendly heat stabilizer and added to PVC. The resulting PVC composites were evaluated for thermal stability using the oven-aging method. The results showed that a lower Mg/Al molar ratio (2.0) improved the initial whiteness and long-term thermal stability of PVC composites compared to higher ratios (2.5, 3.0, and 3.5). Replacing Mg with Zn in the LDHs had a similar effect to that of reducing the Mg/Al ratio. Crosslinking the laminae of LDHs with 5% silane coupling agent KH-560 reduced the surface basicity of LDHs by 79%, increasing the chromaticity index, b*, and thermal stability time of PVC composites by 48% and 14%, respectively. A descriptive relationship was established between the structure and surface basicity of LDHs and the initial whiteness and long-term thermal stability of PVC composites.

Preparation and performance of PVC long‐term heat stabilizer based on the synergistic effect of uracil and metal complexes

AbstractIn order to improve the deficiency of traditional polyvinyl chloride (PVC) heat stabilizer, triazole‐based zinc‐containing complex (abbreviated as [Zn(ttr)(OAc)]) with good compatibility with PVC and a strong ability to absorb HCl was prepared in this paper, which was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) and thermogravimetric analysis (TGA). PVC sheets were prepared by mixing PVC with composite heat stabilizer (DAJ) composed of [Zn(ttr)(OAc)] and 1,3‐dimethyl‐6‐aminouracil (DAU). Different kinds and amounts of common auxiliary heat stabilizers were selected and added to the DAJ system to study the effect of thermally stable system on PVC by Congo red test, Discoloration test, Dynamic thermal stability test, SEM, TGA and Transmittance test and the relevant mechanism was explored. The PVC sheets with DAJ blended by 1.2 phr DAU and 0.8 phr [Zn(ttr)(OAc)] showed relatively excellent coloring properties, long‐term thermal stability, and high light transmittance. Compared with dibenzoylmethane (DBM), 0.5 phr sorbitol and 1.5 phr epoxy soybean oil (ESBO)/Antioxidant 168 showed good synergistic effect with DAJ. Due to the polyhydroxy nature of sorbitol, the thermal stability of PVC was significantly improved, and the transmittance of PVC benefited from the similar miscibility of ESBO long chain. This was also confirmed by TGA and SEM of PVC sheet.

Thermal stabilization of polyvinyl chloride by calcium and zinc carboxylates derived from byproduct of palm oil refining

Calcium and zinc carboxylates were prepared from palm fatty acid distillate, a byproduct of palm oil refining, via metathesis in aqueous ethanol. The formations of both metal carboxylates have been confirmed by infrared spectroscopy and x-ray diffraction analysis. Thermogravimetric analysis has shown that the prepared calcium and zinc carboxylates are practically stable while their weight losses are 14% at 393 °C and 19% at 311 °C, respectively. The efficacy of the metal carboxylates in their mixtures in stabilizing polyvinyl chloride against heat has also been studied by using static and dynamic tests. The calcium to zinc ratio of 4:1 has been found to give the longest stability time under the studied condition. The mixed calcium/zinc carboxylates demonstrate a synergism effect with pentaerythritol. The results reveal that mixed calcium/zinc carboxylates from palm fatty acid distillate are effective in stabilizing polyvinyl chloride against heat.

Development of a Highly Efficient Environmentally Friendly Plasticizer.

The purpose of this work is the synthesis of adipic acid ester and the study of the possibility of its use as a PVC plasticizer. The resulting butyl phenoxyethyl adipate was characterized by Fourier-transform infrared spectrometry, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The compatibility, effectiveness and plasticizing effect of butyl phenoxyethyl adipate in comparison with dioctylphthalate (DOP) were determined. The new environmentally friendly plasticizer has good compatibility with PVC and high thermal stability. The effectiveness of the plasticizing action of adipate based on the glass-transition temperature was 132.2 °C in relation to pure PVC and 7.7 °C in comparison to compounds based on DOP. An increase in the fluidity of the melt of polyvinyl chloride (PVC) compounds in the temperature range of 160–205 °C by 19–50% confirms a decrease in the energy intensity of the processes of manufacturing and the processing of polymer materials containing a new additive.

Effect of isomer and defect structure on the thermal stability of polyvinyl chloride: An experiment and molecular dynamics simulation

The relationship between molecular chain structure and thermal stability of polyvinyl chloride (PVC) was studied by experiment and molecular dynamics (MD) simulation. The experimental results of oven aging test, UV–Vis and 1H-NMR showed that the PVC samples generated fewer conjugated triene and total double bond during aging exhibited better thermal stability. The IR spectra of gas products indicated that thermal aging of PVC mainly generated hydrogen chloride (HCl) and low molecular weight hydrocarbon (CH2) between 50 and 500 °C. The PVC molecular chain model was constructed by MD simulation to study reaction pathways and products during PVC thermal aging, the results further confirmed that HCl and CH2 were the main products of PVC thermal aging. Besides, the thermal aging models of PVC with different isomers and defect structure were also established and calculated based on MD simulation. The results of MD simulation and 13C-NMR indicated that the CCl bond in the syndiotactic structure broke first and the 1,2-dichloride terminal was the most unstable defect structure. In a word, this work paves the way for the observation of the real-time structure evolution of PVC, especially during the aging process.

Rheological properties and dynamic thermal stability ofPVC/La L2/Ca‐Zncomposite stabilizer

AbstractLanthanum complex with curcumin (La L2)/Ca‐Zn composite stabilizer was prepared using La L2and Ca‐Zn stabilizer, in which Ca‐Zn stabilizer was obtained from calcium stearate and zinc stearate at their mass ratio of 5:1. The rheological properties and dynamic thermal stability of polyvinyl chloride (PVC) stabilized by La L2/Ca‐Zn composite stabilizers were estimated through a torque rheometer. The degraded fragments obtained from the torque experiments were measured by Fourier‐transform infrared spectroscopy (FTIR) and ultraviolet–visible (UV‐vis) spectroscopy. La L2had an effective synergistic effect with Ca‐Zn stabilizer. Compared with La L2, La L2/Ca‐Zn composite stabilizer could more significantly improve the rheological properties and dynamic thermal stability of PVC. An optimal synergistic effect could be observed when the mass ratio of La L2with Ca‐Zn stabilizer was about 8:2, in which the plasticizing torque and equilibrium torque of PVC was 33.3 N m and 22.5 N m, respectively, and its dynamic thermal stabilizing time was 25.1 min. The possible thermal stability mechanism of La L2/Ca‐Zn composite stabilizer for PVC was suggested based on the evaluation of FTIR spectroscopy and UV‐vis spectroscopy.

Synthesis of Lanthanum Orotate and its Application as PVC Thermal Stabilizer

The structure of basic lanthanum orotate (LaOr) were characterized by elemental analysis and infrared spectroscopy. The thermal stability of polyvinyl chloride (PVC) was further studied by Congo red method, oven discoloration method and thermogravimetric analysis. The results showed that LaOr could prolong the oven discoloration time of PVC, and the color was not completely blackened until 120 min. It has a good synergetic effect with dibenzoyl methane (DBM), and the best effect is achieved when LaOr/DBM ratio is 1.8/1.2. The thermal decomposition kinetics experiment showed that adding DBM can effectively improve the activation energy of PVC/LaOr. The stabilization mechanism of PVC was studied by absorbing HCl method and infrared spectroscopy. The results showed that LaOr could not only replace the unstable chlorine atoms on PVC, but also promote the long-term thermal stability of PVC by absorbing HCl.

Enhanced the Thermal Stability of Polyvinyl Chloride via Synergistic Effects of Basic Lanthanum Tartrate with Zinc Stearate and Pentaerythritol

Basic lanthanum tartrate (BLT) was synthesized by a simple chemical precipitation method and was characterized by elemental analysis and Fourier transform infrared spectroscopy. The effect of BLT on polyvinyl chloride (PVC) thermal stability has been studied through the Congo red test and the discoloration test. BLT displayed high stabilizing effect and the thermal stabilization time is 24 min when the percentage of BLT in PVC is 4%. The plasticizing ability of BLT is good. Tests indicated that when BLT was used as a stabilizer, the plasticizing time, plasticizing torque and balance torque of PVC were reduced. The BLT was also used to combine with one or more of zinc stearate, calcium stearate and pentaerythritol to form a composite stabilizer. When the mass ratio of basic lanthanum tartrate/zinc stearate/pentaerythritol was set to 3/1/1, the thermal stabilization time and discoloration resistance of the PVC sample were the best, and its thermal stabilization time was 44 min.

Organic tin, calcium–zinc and titanium composites as reinforcing agents and its effects on the thermal stability of polyvinyl chloride

In view of the polyvinyl chloride (PVC) in the processing and molding easy degradation, the stability effect of different components is not good when used alone, and PVC in thermal degradation with the release of hydrogen chloride will lead to the formation of toxic gas dioxins to the environment and human problems. For this purpose, the nanosized titanium dioxide (NT), calcium–zinc (Ca-Zn)*, dipentaerythritol (Dip) and organotin (OT) were modified with butyl titanate (BT), coupling agent to synthesize the composite material and used as the strengthening agent for PVC. The composites and PVC were characterized, and their properties were determined using Raman, XRD, TG, TG-IR, Congo red and DMA. The results showed that the BT/NT/Dip/OT/(Ca-Zn)* complex not only kept the basic configuration of NT particles, but also had strong interaction between components due to BT coupling, which had synergistic effect on PVC. Similarly, BT was involved in the coupling between PVC and Dip/OT, resulting in prolonged initial discoloration time. When 3.8mass%BT/NT, 0.32mass%OT, 0.32mass%(Ca-Zn)* and 0.63mass% Dip were added to the PVC film, compared with blank sample and only 1phr of OT stabilizer, the new composite material was formed. The longest initial discoloration time was observed by Congo red, and the temperature was improved when TG was used to analyze the maximum mass loss rate, and the maximum mass loss rate was reduced by 115%. As the conversion rate reached 1%, the decomposition temperatures of PVC composite film and blank sample were 234.7 °C and 175.2 °C, respectively, indicating that the formed PVC film had excellent thermal stability. TG-FTIR analysis showed that after adding OT at 0.5 phr, (Ca-Zn)* at 0.5 phr and Dip at 1.0 phr, the composite film was around 331.1 °C and 476.6 °C, and the peak strength of CH4 gas released by thermal degradation was 114.0 and 262.0% higher than that of blank sample, respectively. It can be seen that pentaerythritol has a promoting effect on CH4 release of PVC, and the peak strength of CO2 is shifted to the high temperature zone, contrary to the blank sample, there is no formation of hydroxyl or water, which means that the thermal degradation pathway of PVC has changed, and it is possible to inhibit the generation of aromatic hydrocarbons and dioxins. By introducing 3.8 mass% BT/NT composite reinforcement, compared with the blank sample, the observed storage modulus increased by 22.4%, and the mechanical properties of PVC composite material were improved.

Tensile properties, thermal stability, and the mechanism of PVC stabilized with zinc and calcium oxolinic complexes

ABSTRACTTwo novel thermal stabilizers, zinc and calcium oxolinic complexes (Zn(Oxo)2 and Ca(Oxo)2), with superior tensile properties and notable thermal stability effect for polyvinyl chloride (PVC) are reported here. The complexes are synthesized without any organic solvents, and the structures are confirmed as Zn(C13H10NO5)2·H2O and Ca(C13H10NO5)2·3H2O by Fourier transform infrared spectroscopy, thermogravimetric analysis, X‐ray fluorescence spectrometry, and elemental analysis. The PVC samples stabilized with the complexes show superior tensile strength and elongation at break compared with zinc and calcium stearates by tensile test. The results of Congo red test, dehydrochlorination test, and discoloration test show that: (1) Zn(Oxo)2 is better than zinc stearate as thermal stabilizer for PVC; (2) Zn(Oxo)2 and Ca(Oxo)2 show notable synergistic effect with calcium stearate and zinc norfloxacin respectively. The mechanism of the superior tensile properties and notable thermal stability effect is due to the ability of the complexes to absorbing HCl and reacting with PVC chains, which result in the special chain extension of PVC and the delay of autocatalytic effect and zipper‐like dehydrochlorination. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47004.

Synthesis of Zinc Stannate Microcapsules for Preparation of Flame-Retardant PVC Composites

ABSTRACTA multilayer microcapsule [melamine-formaldehyde resin/aluminum hydroxide/zinc stannate] with unique core–shell structure was prepared. Fourier transform infrared, X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscope were used to investigate the chemical structure of the microcapsules, fire retardancy, and thermal stability of polyvinyl chloride with these materials as additives were also investigated. Remarkably, addition of certain amount of melamine-formaldehyde/aluminum hydroxide/zinc stannate microcapsules could evidently increase limiting oxygen index values. The smoke density results showed that polyvinyl chloride containing melamine-formaldehyde/aluminum hydroxide/zinc stannate microcapsules produced less smoke than pure polyvinyl chloride. The morphologies of the residues were revealed by scanning electron microscope, ascertained that the formed char layers on the composites were denser than that of the pure polyvinyl chloride and polyvinyl chloride/aluminum hydroxide/zinc stannate microcapsule composites. Furthermore, the mechanical properties of polyvinyl chloride/melamine-formaldehyde/aluminum hydroxide/zinc stannate microcapsule composites were observably improved, highlighting its promising potential in industrial applications.