Figure - available from: Journal of Inorganic and Organometallic Polymers and Materials
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The contour plots illustrating slope of the viscosity-shear rate curve of the nanocomposites when changing parameters simultaneously
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In this work, torque rheometry was employed to evaluate rheological properties of the PVC/NBR blends containing nanoclay. In this way, the individual and interactive effects of formulation parameters including type and content of nanoclay (NC) and also NBR content were studied using response surface approach. Furthermore, the experimental data were...
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The flow properties of unplasticized PVC are know to be sensitive to processing conditions, so on-line rheometry under processing conditions is indicated to obtain data for numerical simulations of the extrusion process. Wall slip is also known to be an important factor in uPVC extrusion. An on-line slit rheometer has been built with interchangeabl...
Citations
... Most of the commercial thermal insulators are made of nitrile rubber (NBR)/poly (vinyl chloride) (PVC) blend foams (Suriyachai et al., 2013). The blending of NBR with PVC improves the ozone, chemicals and thermal aging resistances of NBR (Moghri et al., 2017;Luo et al., 2019). However, NBR/PVC polymer foams still shows some disadvantages (Khalil et al., 2012;Samui et al., 2006;Chai and Zhang, 2013), which comprise restricted use at higher temperature, poor fire and thermal aging resistances, friability, and susceptibility to thermal cycling and ultraviolet light. ...
Thermal insulation and excellent weatherability microcellular foams based on lightweight polymer are successfully developed from chlorinated polyethylene rubber/polyvinyl chloride (CM/PVC) compounds through electron beam irradiation cross-linking and chemical foaming technology. The effect of electron beam irradiation on the blends of CM/PVC foam prepared with different compositions starting from 70:30 to 50:50 (CM:PVC) with varied radiation doses from 30 to 70 kGy and varied chemical blowing agent contents from 10 to 20 phr has been studied. The aim was to investigate the influence of the different blending ratio, the chemical blowing agent content and the irradiation dose on physical and mechanical properties and morphology of the cellular structure in the produced foams. Thermal conductivity of CM/PVC compounds foams achieved in this study is as low as 0.0374W/mK.
PVC composites are frequently and widely used in numerous engineering applications because they offer a cost-effective and versatile solution with improved mechanical, thermal, and barrier properties for various applications. Investigating the thermal characteristics, thermal stability, and thermal degradation of PVC-based composites is essential to ensure their optimal performance, safety, and durability in polymer material science. The current study briefly explains the thermal properties and degradation mechanism of PVC and then focuses are placed on the composites with PVC matrix. In particular, the thermal characteristics of different composite formulations and strategies based on different reinforcements were presented and compared within each strategy and in between. This overview will help to gain a profound understanding of the current state of PVC-based composites and nanocomposites in the context of thermal properties and thermal degradation to determine the best formulation, processing processes, and conditions of such composite materials.
Plasticized filled poly(vinyl chloride) (PVC) blends incorporating acrylonitrile-butadiene rubber (NBR) as an elastomeric crosslinking co-agent were subjected to gamma radiation by a Co60 source for total doses 25 to 100 kGy. Changes in total insoluble contents, physicomechanical properties (before and after thermal aging), morphology, spectroscopy, and dynamic mechanical behavior as a function of NBR loading and total dose were investigated. An increase in total insoluble contents with both NBR loading and total dose indicates that within the parameters of the study, the blends underwent crosslinking as the predominant effect with an increase of hardness. Unaged mechanical properties (tensile strength, Young’s modulus, and elongation at break) of the blends were significantly modified. These same properties, after aging at 90 °C, 168 h are again modified due to further crosslinking reactions above the glass transition temperatures. The obtained results indicate that there exists a loading range for NBR for which an optimal combination of room temperature and aged mechanical properties may be obtained. Abrasion resistance of the blends improves due to the formation of chemically bonded networks. The mechanism of the crosslinking reaction was elucidated by Fourier transform infrared spectroscopy. Electron scanning microscopy shows single-phase blend morphologies for all blends and reveals a reduction in matrix ductility on crosslinking. Dynamic mechanical analysis conducted to study the change in loss tangent, storage modulus, and loss modulus at 100 kGy total dose shows an increase in these parameters and that the modification of physicomechanical properties are due to both crosslinking as well as enhanced interaction between PVC and NBR.
In this paper, the graft copolymer PVC-g-PMMA composed of PVC main chain and PMMA side chain is synthesized by atom transfer radical polymerization. And it is added to the polyvinyl chloride/nitrile rubber (PVC/NBR) to prepare the PVC/NBR/PVC-g-PMMA composite film. The effects of PVC-g-PMMA on the mechanical properties, heat-resistant oxygen aging properties and thermal stability of PVC/NBR composite film are investigated. The mechanical performance test results show that after adding PVC-g-PMMA, the mechanical properties of the PVC/NBR composite film is improved. The tensile strength increases by 20.13%, and the elongation at break increases by 14.28%. The test results of heat-resistant oxygen aging performance indicate that after 96 hours of aging, the tensile strength of the PVC/NBR/PVC-g-PMMA composite film increases by 4.88% compared with the PVC/NBR composite film. The thermal stability test results illustrate that after adding PVC-g-PMMA, the residual weight of the PVC/NBR composite film increases by 0.7%, and the maximum thermal decomposition rate reduces by 0.12%/°C. It shows that PVC-g-PMMA not only improves the mechanical properties, thermal stability and aging resistance of PVC/NBR composites, but also enhances the market competitiveness of PVC/NBR composites. It expands the application of PVC/NBR composite materials in the field of decoration and protective coatings.
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 was relieved.
Hybrid rubber nanocomposite blends based on (80/20) XNBR/EPDM containing 5 phr Cloisite 10A, 15A 20A, 25A, 93A, 30B, carbon black and silica nanofiller and two types of EPDM-g-MA and ENR 50 containing 5 phr was prepared by a two roll mill. A rheometer test was used to study the curing of the blends, the tensile test was used to study the mechanical strength of the nanocomposite and XRD, FESEM and TEM tests were used to evaluate and observe the morphology of the nanocomposite blends prepared. The results of the rheometer test show that the Cloisite 30B nanofiller, in addition to increasing the torque and optimum cure time, decreased compared to other nanofillers. The results of the XRD test showed that the ENR50 compatibilizer with the Cloisite 30B nanofiller compared to other nanofillers, compared to the EPDM-g-MA compatibilizer, significantly increased the openness of the layers by 2.21 nm. The results of FESEM and TEM confirmed the better distribution of Cloisite 30B nanoparticles in the XNBR/EPDM sample containing ENR 50 compatibilizer. Also, XRD evidence showed that the opening of the nanofiller layers of Cloisite 30B was higher the other nanofillers. This result is consistent with microscopic observations. In addition, all nanoparticles are located in the XNBR phase. The results of the tensile test showed that the modulus and tensile strength of nanocomposite containing Cloisite 30B nanofiller and ENR 50 compatibilizer with other nanocomposites increased.
A thermoplastic elastomeric blend from acrylonitrile butadiene rubber (NBR) and plasticized polyvinyl chloride (PVC) in the ratio (1:1) was prepared. This blend was loaded with different concentrations of mechanically ground fine powder of Moringa oleifera (MO) leaves that have an antibacterial activity, to form polymeric-based composites. The prepared composites were characterized to investigate their surface morphology and swelling behaviors. Besides, their mechanical and thermal properties were investigated. The tensile and hardness properties increased upon loading (MO) up to 20 phr. Thermogravimteric analysis (TGA) and derivative thermogravimetry (DTG) curves did not show complete deterioration upon introducing MO into the polymeric matrix. Differential scanning calorimetry (DSC) showed some shifts in the endo- and exotherms of DSC curves for PVC and NBR/PVC blend in the presence and in the absence of M. oleifera. The samples were tested biologically against Gram-positive and Gram-negative bacteria to show significant antibacterial activities. The antibacterial potency of the NBR/PVC blend increased with elevating the concentration of MO powder from 5 to 25% by mass.
