INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Hao Yang,Ping He,Henglun Cheng,Baoqing Shentu
To promote the anti-aging performance of thermoplastic vulcanizates (TPVs) versus ultraviolet (UV)/O3 exposure, a nano-TiO2-loaded antioxidant (TiO2-KH570-MB) was prepared by a thiol–ene reaction between 2-mercaptobenzimidazole (MB) and modified nano-TiO2 (TiO2-KH570). Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis demonstrated the chemical linkage between MB and modified nano-TiO2, and the loading amount of MB was approximately 5.19 wt %. The contact angle test showed that the surface hydrophobicity of TiO2-KH570-MB was significantly increased due to the immobilization of MB. Scanning electron microscopy revealed that TiO2-KH570-MB was uniformly distributed in the TPV matrix. The anti-aging property of TPV compounds was tested in the device with high-intensity ultraviolet radiation and high-concentration ozone. The effects of UV/O3 comprehensive aging on the TPV compounds were evaluated by means of the variations of surface morphology, tensile test, hardness, gel content, and carbonyl index with aging time. On the basis of the aging behavior, we concluded that TPV/TiO2-KH570-MB exhibited excellent stability against UV/O3 aging, due to the homogeneous dispersion, low level of migration, and low volatility of TiO2-KH570-MB.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2018
·
IF 3.193
Hao Yang,Hui Zhang,Henglun Cheng,Baoqing Shentu
Nano-TiO 2 immobilized antioxidant (TiO 2 -KH550-AG) was prepared to improve the ageing resistance of thermoplastic vulcanizate (TPV) exposed to UV/O 3 . TiO 2 nanoparticles were firstly modified with 3-aminopropyltriethoxysilane (KH550) and then reacted with the antioxidant , 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid (AG), through the acyl chloride reaction followed by the amidation. FT-IR, XPS and TGA measurements confirmed that the antioxidant (AG) was chemically immobilized onto the nano-TiO 2 surfaces. TPV/TiO 2 -KH550-AG nanocomposites were prepared by melt mixing. SEM observation showed that TiO 2 -KH550-AG was homogeneously dispersed into the matrix of TPV. The UV/O 3 ageing test of the samples was carried out in the environment with constant UV intensity of 1.40 mW/cm 2 and ozone concentration of 100 ± 4 mg/m 3 . The ageing resistance behavior of the TPV/TiO 2 -KH550-AG nanocomposites was evaluated by the changes of surface morphology , mechanical properties and carbonyl index during the UV/O 3 ageing test. It was observed that the TPV/TiO 2 -KH550-AG exhibited high stability during the process of UV/O 3 ageing. The results revealed that the anti-ageing efficiency of TiO 2 -KH550-AG was superior to the mixture of the corresponding AG and modified TiO 2 , owing to the better dispersion and migration resistance of TiO 2 -KH550-AG.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Jiarong Huang,Jianfeng Fan,Daosheng Yuan,Shuidong Zhang,Yukun Chen
Blending with elastomers is one of the most effective strategies for toughening polylactide (PLA) but faces the challenge of a sharp decline in stiffness. In this work, PLA/epoxidized natural rubber (ENR)/silica (SiO2) thermoplastic vulcanizates (TPVs) with balanced stiffness–toughness were designed via dynamic vulcanization. The PLA/ENR/SiO2 TPVs exhibited a cocontinuous structure in which SiO2 nanoparticles were regulated to selectively distribute in the ENR phase. SiO2 nanoparticles enhanced the mechanical strength and thickness of ENR network, resulting in efficient toughening of PLA without sacrificing its stiffness. With 20 phr SiO2, the TPVs showed an excellent cryogenic impact toughness of 54.5 kJ/m2 at 0 °C, which was 8.3 times that of the PLA/ENR blend. Meanwhile, incorporation of SiO2 made the TPVs sustain a high retention rate of the tensile strength (98.2%). The synergistic toughening mechanism of SiO2 nanoparticles and ENR was investigated via a series of testing methods, proposing a feasible approach to fabricate high-performance TPVs.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Yongjian Zhao,Haonan Shi,Martin Hoch,Jie Mao,Xinyan Shi
Thermoplastic vulcanizates (TPVs) have been widely studied and applied in recent years because of their excellent elasticity and re-processibility similar to those of thermoplastics. However, its dynamical vulcanization processing normally requires an expensive twin-screw extruder with a very high L/D ratio. In this paper, a kind of thermoplastic vulcanizate concentrate (TPVC) with very high rubber phase content and low hardness was prepared by using highly oil-extended ultra-high molecular weight ethylene propylene diene rubber (EPDM) dynamically cured by peroxide and a low melt index polypropylene (PP) and extra oil softener. Then a new kind of high purity TPV with a wide hardness range was fabricated by using this TPVC simply melt blended with various contents of PP. The mechanical and recycling properties, rheological responses, phase morphology, crystallization, thermal stability and UV radiation resistance were systematically studied. In addition, because TPVC is filled with a large amount of white oil, the process parameters can be controlled reasonably by studying the distribution coefficient of white oil in the two phases.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Mengmeng Xu,Chengzhong Zong
It is challengeable to obtain shape memory effect in the traditional thermoplastic vulcanizate (TPV) with sea-island microstructure. Herein, we successfully achieved shape memory behavior in the type of ethylene propylene diene monomer/polypropylene thermoplastic vulcanizate (EPDM/PP TPV) compatibilized by the graft products of magnesium maleic (MgMA) and maleic anhydride (MAH) on the interface of EPDM/PP. MgMA and MAH derived from the in situ neutralization reaction of maleic acid (MA) with magnesium oxide (MgO) and the dehydration reaction of MA respectively. In this paper, the mole ratio of MA and MgO on the performance of EPDM/PP TPV was studied. With the incorporation of MA and MgO, the mechanical property and shape memory performance were improved. The result of DMA, FTIR, and SEM verified the successful graft reaction of MgMA and MAH on the polymer chains. The compatibilized EPDM/PP TPV achieved the improved mechanical property of tensile strength (12.9 MPa) and elongation at break (583.5%), the increased R f of 96.2% and R r of 86.7% at the tailoring mole ratio of MA:MgO (1:1.5).
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Mengmeng Xu,Yingxia Zong,Chengzhong Zong
The effects of magnesium maleate (MgMA) and maleic anhydride (MAH) on the interfacial interaction and the shape memory properties of ethylene propylene diene monomer (EPDM) and polypropylene (PP) thermoplastic vulcanizate (TPV) with sea island structure prepared by dynamic vulcanization were investigated in this study. PP matrix could maintain the temporary shape of TPVs and the crosslinked EPDM phase supplied stress to drive the deformed shape recovery during the shape memory process. MgMA and MAH grafted on PP and EPDM chains verified by FTIR, DMA and SEM, which improved the interfacial compatibility of EPDM and PP and enhanced the efficiency of stress transfer in the shape memory process. The shape fixity ratio (R f ) and shape recovery ratio (R r ) of TPVs compatibilized by MgMA and MAH were almost above 80%. The shape memory property and the mechanical performance of TPVs were all improved compared to that of the sample without compatibilization .
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 21
·52219
·
IF 3.057
Yongyin Cui,Hongwei Pan,Changrui Shi,Huichao Zhuang,Qingfu Wang,Chengzhong Zong
To simplify the production process of thermoplastic polyurethane (TPU)/methyl vinyl silicone rubber (VMQ)-based thermoplastic vulcanizate (TPV), a series of block TPUs with different hydroxybutanyl terminated polydimethylsiloxane (PDMS) content were used as the matrix to increase the essential compatibility. The impact of microstructure and macroscopic properties was explored. PMDS promoted the microphase separation of TPU, which increased the essential compatibility in TPVs. The essential compatibilization effect of PDMS made the tensile strength retention proportion of TPV relative to the raw material TPU at 40%, but the elongation at break could reach 192%, which had an excellent toughening effect. Moreover, PDMS made the limiting oxygen index of TPV-323 reach 27%. The analysis of the carbon layer proved that the Si element formed a silicon oxycarbon layer with excellent flame retardancy on the surface.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
POLYMER
·
2020
·
IF 4.231
Xinke Zhong,Yihu Song,Qiang Zheng,Wanjie Wang
Gum vulcanizates exhibit Payne effect and weak strain overshooting behavior, which is usually forgot in rubber industry. Herein the Payne effect of butadiene rubber (BR) vulcanizates is investigated for clarifying the effect of crosslinking density and sol content mediated by using coagent in conjugation with dicumyl peroxide. Toluene extraction and paraffin swelling of the vulcanizates are performed for clarifying the contribution of sol fraction and chains entanglement. The results show that the Payne effect and weak strain overshooting of gum vulcanizates are closely related to effective crosslinking density rather than network defects. This work is helpful for understanding the nonlinear rheological responses of the gum vulcanizates with defective network structure.
研究领域:
材料科学
·
高分子科学
·
流变学
✓ 已验证
产品关联
DOI
高影响因子
Polymer-Plastics Technology and Materials
·
2020
·
IF 0
Huiyu Bai,Jiajun Lu,Bo Li,Shengwen Zhang,Wei Wang,Piming Ma,Weifu Dong
A novel thermoplastic vulcanizate (TPV) based on poly (vinylidene fluoride)/poly (ethylene–butylacrylate–glycidyl methacrylate) (PVDF/PTW) (30/70 w/w) blends has been fabricated by dynamic vulcanization due to selective cross-linking of PTW by adding small amount of 3-(2-Aminoethylamino) propyldimethoxymethylsilane (KH602). The blends with KH602 had the solid-like behavior at low frequency and enhanced viscosities and dynamic modulus. The TPV exhibited a quasi co-continuous morphology with PVDF dispersed in PTW matrix, which was different from that of PVDF/PTW blend, exhibiting phase-separated morphology with PVDF dispersed in unvulcanized PTW matrix. The resulted TPVs displayed excellent mechanical properties, and excellent strain recovery, which will be a promising coating material, especially wire and cable applications.
研究领域:
材料科学
·
高分子科学
·
化学工程
✓ 已验证
产品关联
DOI
BIOTECHNOLOGY AND APPLIED BIOCHEMISTRY
·
2022
·Vol. 70
·期 2
·697-706
·
IF 2.724
Shijin Wu,Bijiao Wang,Hongde Yan
Asymmetric reduction of ( R )-carvone and ketoisophorone by an engineered ene-reductase from Galdieria sulphuraria (GsOYE) combined with glucose dehydrogenase for NADPH regeneration were studied. A semi-rational protein engineering was used to enhance the activity and selectivity of GsOYE. Upon the sequence alignment and molecular docking results, two amino acid residues at positions 66 and 270 were selected as saturation mutation sites. Finally, a single substitution variant of GsOYE-N270A with complete conversion (100%) and diastereoselectivity (de p >99%) for reduction of ( R )-carvone and a double substitution variant GsOYE-Y66P/N270H with improved stereoselectivity for reduction of ketoisophorone were obtained.
研究领域:
生物化学
·
蛋白质工程
·
催化
·
酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2023
·Vol. 41
·期 12
·1947-1957
·
IF 4.3
Shi Xuan-Yu,Sun Shi-Hao,Yang Li,Zhong Jun,Yu Xiao-Feng,Xu Zheng,Zuo Min,Song Yi-Hu,Zheng Qiang
Incorporation of carbon black (CB) in natural rubber (NR) enhances the Mullins effect and Payne effect of their vulcanizates, but the strain softening mechanisms and the microstructure evolution in the vulcanizates have not been clearly concluded so far. We investigate the Mullins effect and Payne effect of CB filled NR vulcanizates by using cyclic tensile tests at different temperatures and dynamic rheological measurements combined with simultaneous electric conduction. During cyclic stretching, the normalized recovery hysteresis energy and accumulative softening energy for NR/CB vulcanizates with different loadings can be both superimposed on a master curve, indicating that the Mullins effect is mainly dominated by the rubber matrix. The irreversible simultaneous resistance evolution also reveals that the structural evolution of nanoparticles (NPs) network is not directly related to the Mullins effect. Moreover, the extension of linear viscoelastic region and the hysteresis of Payne effect for filled vulcanizates subjected to cyclic stretching indicate the destruction of CB aggregated structure and the interfacial layers between CB and rubber chains during cyclic stretching. This investigation would be illuminating for the microstructure evolution and strain softening of rubber nanocomposites under harsh service conditions.
研究领域:
材料科学
·
高分子科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Xinke Zhong,Yihu Song,Qiang Zheng
Rubber nanocomposites exhibit strain softening under large-amplitude oscillation shear and large-strain cyclic tension while the mechanisms remain unresolved. Herein we systematically investigate the Payne effect and Mullins effect of unfilled and silica filled butadiene rubber (BR) vulcanizates to clarify the impacts of crosslinking density, sol fractions, and filler content. During large-amplitude oscillation shear, the critical strain amplitude for the onset of Payne effect is closely related to storage modulus in the linear viscoelastic region. During cyclic tension deformations, the recovery hysteresis energy and accumulating softening energy are involved in the local deformation of the rubber matrix, which is promoted by the filler phase. These findings are illuminative for optimizing performance of rubber nanocomposite products by controlling the nonideal network structure of viscoelastic rubber matrix.
研究领域:
材料科学
·
高分子科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）