JOURNAL OF ELASTOMERS AND PLASTICS
·
2023
·
IF 1.7
Zheqing Gong,Lijun Chen
Modified latex is prepared via the soap-free emulsion polymerization of ethyl acetate (VAc) and vinyl versatate (VeoVa10). DFHMA is used as modified monomers. The composite surfactants of SR-10 and ANPEO-10 are used as the composite emulsifiers. The polymerization is initiated by potassium sulfate (KPS). The structure of latex film was characterized by Fourier transform infrared spectroscopy (FTIR). The latex films were tested by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA) determinator. The particle size of the latex emulsion particle size is determined by the Zetatrac dynamic light scatter. Results show that the optimum condition of preparing the modified latex can be obtained, i.e. the amount of emulsifier is 4.0%; the mass ratio of SR-10 to ANPEO-10 is 1:1; the amount of initiator is 0.5%; the mass ratio ofVAc to VeoVa10 is 1:1; the amount of DFHMA is 5.0%. The appearance of the latex is blue and translucent with a small particle size. The conversion rate is more than 98%. Compared with the conventional latex, the hydrophobicity and heat resistance of the film have been improved. Moreover, the latex has good chemical stability and mechanical stability.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 21
·4896
·
IF 3.057
Yiren Pan,Meng Zhang,Jian Zhang,Xiaoyao Zhu,Huiguang Bian,Chuansheng Wang
In this paper, the areca fiber was extracted by physical and chemical treatment, and then the areca fiber/natural latex composite was prepared by natural latex impregnation technology. In order to combine areca fiber and natural rubber latex better, three silane coupling agents with different action mechanism were selected: Si−69, KH550, and KH570 which were used to treat the areca fiber/natural latex compound. The results show that the silane coupling agent can change the surface of the fiber from hydrophilic surface to organophilic surface, making the bonding of areca fiber to natural latex more closely. At the same time, the mechanical properties, physical and mechanical properties, swelling properties, and dynamic viscoelastic properties of the tightly bonded areca fiber/nature latex composites were improved. After observing the micro-structure through a scanning electron microscope, it was found that the three silane coupling agents could effectively bind areca fiber and natural latex to enhance the performance of the composite material, of which Si−69 performed best, and the tensile strength and tear strength of the composite increased by 21.19% and 12.90% respectively.Keywords:areca fiber;natural latex;silane coupling agent
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Batteries-Basel
·
2023
·Vol. 9
·期 6
·304
·
IF 4
Ruixue Liu,Wenkang Liu,Jichao Chen,Xiangli Bian,Kaiqi Fan,Junhong Zhao,Xiaojing Zhang
Ionic conductive hydrogels with good conductivity and biocompatibility have become one of the research highlights in the field of wearable flexible sensors and supercapacitors. In this work, poly(methacrylic acid–methyl methacrylate)-reinforced poly(sodium acrylate–vinyl phosphonic acid) composite hydrogels (P(AAS-VPA)/PMMS) were designed and tested for strain sensor or supercapacitor applications. The results showed recoverability for 20 cycles of tension and compression experiments, an excellent breaking strain of 2079%, and ionic conductivity of 0.045 S·cm−1, demonstrating strong support for the application of the P(AAS-VPA)/PMMS hydrogel in strain sensors and supercapacitors. The composite hydrogel exhibited outstanding sensing and monitoring capability with high sensitivity (GF = 4.0). The supercapacitor based on the P(AAS-VPA)/PMMS composite hydrogel showed excellent capacitance performance (area capacitance 100.8 mF·cm−2and energy density 8.96 μWh·cm−2) at ambient temperature and even −30 °C (25.3 mF·cm−2and 2.25 μWh·cm−2). The hydrogel has stable electrochemical stability (1000 cycles, Coulomb efficiency > 97%) and exhibits electrochemical properties similar to those in the normal state under different deformations. The excellent results demonstrate the great potential of the P(AAS-VPA)/PMMS composite hydrogel in the field of strain sensors and flexible supercapacitors.Keywords:supercapacitors;latex particles;sensitivity;capacitance performance
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Yongqiang Wang,Kai Du,Bo Liu,Changhui He,Baoming Zhao,Zhenggang Xiao
The gun barrel erosion caused by the burning of high energy propellants is becoming increasingly severe, significantly reducing the useful life of gun barrel. In order to address this problem, erosion reducing additives, including TiO 2 , paraffin, polyurethane or a combination of these, were introduced into the gun propellant or propellant charge system to alleviate the gun barrel erosion. In this article, a new type of flexible phase change composite materials (FPCMs) having excellent thermal stability and superior mechanical performance was successfully designed by incorporating paraffin/BN@PMMA (microPCMs) mixed with different binders of waterborne polyurethane (WPU), carboxylic butadiene-styrene latex (cBSL), and butadiene-styrene latex (BSL) on the fabric surface and applied as protective liners of cartridge case. Therein, the microPCMs was constructed with paraffin as the core and polymethyl methacrylate (PMMA) enforced by nano boron nitride (BN) as the shell by Pickering emulsion polymerization method. The morphology, chemical composition , and phase change behaviors of these prepared FPCMs were analyzed by SEM, FTIR, and DSC , respectively. Results show that these microPCMs with spherical structure but a little rough surface could be evenly distributed in the warp and weft structure of pristine fabric. The resulting FPCM sample containing WPU has the highest phase change latent heat of 38.77 J/g among these FPCMs. Additionally, TG and isothermal TG experiments reveal that the incorporation of binders has a positive effect on FPCMs thermal stability and FPCM sample containing cBSL exhibit the most remarkable thermal stability. The tensile experiments demonstrate that these FPCMs display the desirable mechanical performance and exhibit brittle fraction model. The tensile strength and elongation at break of FPCMs can be enhanced by the introducing of these binders. Pretreating pure fabric with gelatin is proved to be the most effective way in improving the mechanical performance of FPCMs. Herein, FPCM containing WPU has the highest ultimate tensile strength that can be up to 293.53 MPa. The novel flexible phase change composite materials could be a promising candidate to be used as protective liners to reduce the gun barrel erosion induced by the combustion of high energy propellants.
研究领域:
材料科学
·
热能工程
·
兵器科学与技术
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2015
·
IF 3.562
Zefeng Wang,Zhonggang Wang
Core–shell structured latex nanoparticles containing perfluoroalkyl and cross-linkable groups in the shell layer are prepared by two-step emulsion polymerization method. Specifically, the emulsion copolymerization of isobornyl methacrylate (IBOMA) and butyl acrylate (BA) leads to core particle, on which the mixture of IBOMA, BA and fluorinated acrylate monomer is copolymerized with glycidyl methacrylate and acrylic acid , respectively, to generate epoxy- and carboxyl-containing fluorinated latex nanoparticles. The contents of fluorine and cross-linkable monomer are adjusted over a range from 0 to 12 wt%, and from 0 to 20 mol%, respectively. The core–shelled nanostructures of latex particles are confirmed by dynamic light scattering and high-resolution TEM. After thermal treatment, the cross-linked films exhibit significantly improved thermal and hydrophobic stability. Moreover, it is found that, in comparison with the non-cross-linked film, a suitable cross-linking degree is advantageous for the segregation of fluorinated groups on the film surface. The cross-linked film with 6 wt% fluorine exhibits a low surface tension of 17.7 mN/m, even lower than that of polytetrafluoroethylene (18.5 mN/m), owing to the high enrichment of fluorine, as evidenced by XPS , ATR-FTIR and AFM measurements.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Linlin Du,Peng Gao,Yide Meng,Yuanli Liu,Shangwang Le,Chuanbai Yu
Pyrrole (Py) is easily agglomerated during the polymerization process, affecting its performance. In this paper, polypyrrole/monodispersed latex sphere (PPy/MLS) composites were prepared using in-situ polymerization for the adsorption of hexavalent chromium (Cr(VI)). The specific surface area of PPy/MLS (39.30 m2/g) was increased relative to that of PPy (24.82 m2/g), thus providing more effective adsorption sites. In addition, the adsorption properties of Cr(VI) under different conditions, including Py content, pH of the aqueous solution, and PPy/MLS dosage, were investigated to reveal the adsorption mechanism. The results showed that PPy/MLS possessed high Cr(VI) adsorption capacities when the Py content was 50 wt %. The maximum adsorption capacity was 343.64 mg/g at pH 2.0 and 25 °C. Remarkably, the adsorbents exhibited an excellent removal rate of Cr(VI) after three cycles of adsorption–desorption (over 99%), suggesting that the adsorbents had exceptional recyclability. Furthermore, the adsorption process followed quasi-second-order kinetics and Langmuir isothermal adsorption model. The high adsorption performance, sustainability, and cost-efficiency make this adsorbent a promising candidate for large-scale Cr(VI) contaminant removal.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Pigment & Resin Technology
·
2024
·
IF 1.3
Lijun Chen,Wanting Zhao,Zheqing Gong
PurposeThe traditional vinyl ester of neodecanoic acid-vinyl acetate (VeoVa10-VAc) copolymer latex is a linear structure with poor film formation, thus causing solvent resistance and wear resistance of the latex film to be poor. This study aims to investigate the use of cross-linkers in emulsion polymerization to modify the latex. During the course of film formation, the reactive functional groups react to form cross-linkage. The network structure can effectively improve the compactness of the resin, thereby greatly improving the water resistance, solvent resistance and heat resistance of the resultant film. In addition, the reactive emulsifier is used to replace the conventional emulsifier. Thus, the drawbacks of the conventional emulsifier molecules migrate and desorb can be avoided when the polymer latex is stored.Design/methodology/approachThe cross-linked VAc-VeoVa10 latex has been synthesized with the reactive surfactants, in which VAc and VeoVa10 are used as the main monomers and ethylene glycol dimethacrylate (EGDMA) was used as the cross-linked monomer. Potassium persulfate (KPS) and mixed surfactants of alkyl allyl polyoxyethylene ether ammonium sulfate (JS-20) and allyl nonyl phenol polyoxyethylene ether (ANPEO-10) were used as the initiator and emulsifier, respectively. The structure of resultant latex film was characterized by Fourier transform infrared spectroscopy. The latex films were tested by thermogravimetric analysis, differential scanning calorimetry and contact angle (CA). The particle size and its distribution of the latex were measured by the nano particle size analyzer.FindingsThe factors that had an influence on the properties of the latex and the film were investigated in detail. The stability of the resultant latex is good. The average particles of the latex and its distribution are small and uniform, respectively. In comparison with the conventional latex film, the thermal stability and hydrophobicity of the resultant latex film are improved obviously.Practical implicationsThe resultant latex can be used in both the waterborne interior and exterior wall coatings, pickering stabilized waterborne polymer dispersions, polymer powders, environmentally friendly polymer-modified waterproof mortar and other fields, which can be satisfied with the high demand of thermal stability and hydrophobicity.Originality/valueThe modification of poly (VAc-VeoVa10) by reactive emulsifier and cross-linker is seldom reported. In this study, the cross-linked poly (VAC-VeoVa) latex is prepared through the reactive surfactants, with VAc and VeoVa10 used as the main monomers and EGDMA used as the cross-linked monomer. KPS and mixed surfactants of JS-20 and ANPEO-10 are used as the initiator and emulsifier, respectively.
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 SCIENCE SERIES B
·
2024
·Vol. 65
·期 6
·836-841
·
IF 1
Lijun Chen,Zheqing Gong
Abstract The cross-linking acrylic polymer latex based on methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate, and hydroxyethyl acryloylurea was prepared by soap-free emulsion polymerization with sodium 2-acrylamido-2-methylpropanesulfonate and allyloxy alkyl polyoxyethylene ether ammonium sulfate (SR-10) used as the reactive emulsifiers. Glass transition temperature of the latex film prepared is 20°C. The average particle size of the latex is 64 nm and its dispersion index is 0.085. The optimum conditions of preparing the latex were found. In comparison with the conventional latex, the heat and water resistance of the resultant latex have been improved.
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
COLLOID AND POLYMER SCIENCE
·
2020
·Vol. 298
·期 9
·1263-1271
·
IF 1.536
Wei Yan-Chan,Xia Jie-Hui,Zhang Ling,Zheng Ting-Ting,Liao Shuangquan
Dipping product of natural rubber (NR) latex has superior comprehensive properties superior to those made from synthetic latex. Compared with synthetic latex, the component characteristics of NR show the existence of non-rubber components (NRC). In this paper, NRC, mainly proteins and phospholipids, are separately removed by enzyme treatment to study their effect on the film formation behavior of natural rubber latex. The changes of NR latex particles are in situ visualize by using freeze-drying SEM technology and AFM during the film formation process. The results demonstrate that contact, deformation, and coalescence of latex particles occur more readily after the removal of proteins and phospholipids. It shows that removing NRC can quicken NR film formation. However, the mechanical properties of the NR film decrease in the absence of NRC. Based on the research, a film formation mechanism for NR latex is proposed, which can provide a more insightful understanding toward the structure-property relationship of NR film.
Graphical abstract
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
COLLOID AND POLYMER SCIENCE
·
2017
·Vol. 295
·期 2
·353-362
·
IF 1.723
Bai Long,Huan Siqi,Zhang Xiao,Jia Zhao,Gu Jiyou,Li Zhiguo
The synthesis of structured latex particles containing hydrophilic poly(vinyl acetate) (PVAc) cores and hydrophobic poly(styrene) (PS) shells mediated by a controllable transition layer was reported. A transition layer was fabricated onto PVAc cores by introducing a coupling monomer and butyl acrylate (BA), prior to polymerization of second-stage St-based monomer mixture. While such structured PVAc/PS latex particle obtained was thermodynamic non-equilibrium, straightforward synthetic route of the transition layer can be optimized so that the particle morphology is kinetically achievable. Analysis by transmission electron microscopy shows that the particle morphology is highly influenced by both the transition layer composition and PS-based polymer composition. Two-phase particle morphology without transition layer was an inverted acorn-like structure with single PS core wrapped by PVAc shells. The particle morphology mediated by transition layer varied from that of a broken egg shell-like structure with PS-based coating, over intermediate structures in which uniform PS protuberances surrounded PVAc cores, to core/shell structure with single PVAc core. This general approach may offer a number of possibilities for design and synthesis of kinetically controllable phase-separation morphologies for a variety of applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Yan-Chan Wei,Ding Zhu,Wen-Yi Xie,Jie-Hui Xia,Meng-Fan He,Shuangquan Liao
Natural rubber (NR), an important source of elastomeric material, has superior comprehensive properties compared to synthetic high cis -1, 4-polyisoprene, which are attributed to its peculiar architecture. However, it is a challenge to identify the precise structure of NR, especially the structure of NR particles, as there are no direct characterization methods to perform in-situ investigation of structure of NR particles at an intact state. In this study, we used cryogenic transmission electron microscopy (cryo-TEM) to directly explore the morphology of NR particles existing in the latex without drying or chemical fixation. Then, the spatial organization of proteins and phospholipids on the surface of NR particles was visualized by stochastic optical reconstruction microscopy (STORM). The results show that NR particles are spherical particles with an average particle size of 88 ± 15 nm, and the exterior of NR particles is a mixed monolayer of proteins and phospholipids (ca. 4.6 ± 0.77 nm in thickness). Thus, a more complete model for the Hevea brasiliensis rubber particles was proposed. Moreover, we explicated the relationship between the particle size of NR particles, molecular characteristics, and mechanical properties of NR. The M n and M w of small rubber particles (SRPs) with a particle size of 106 nm are (1.56 ± 0.06) × 10 6 g/mol and (2.21 ± 0.07) × 10 6 g/mol respectively, which are much larger than those of the large rubber particles (LRPs) with a particle size of 628 nm ( M n : (0.41 ± 0.05) × 10 6 g/mol; M w : (1.63 ± 0.10) × 10 6 g/mol). After vulcanization, the SRPs have better mechanical properties. Compared with LRPs, SRPs exhibit a 4.3-fold increase in tensile strength (from 5.7 to 24.6 MPa) and a 3.5-fold increase in toughness (from 12.9 to 44.9 kJ/m 2 ). This work not only provides rational design for the new biomimetic synthetic rubber with unique hierarchical structures and excellent properties, but also offers a new possibility for tuning the mechanical properties of NR by preparation of LRPs/SRPs blend of various ratios.
研究领域:
材料科学
·
生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2017
·
IF 1.591
Baijun Liu,Shicheng Sun,Mingyao Zhang,Huixuan Zhang
Particle coagulation technology is a facile approach to prepare large-scale and narrowly dispersed polymer particles. However, diverse shapes such as ellipsolid, snowman, dumbbell, and trimer among others were obtained if the cross-linker was directly added into the initial reaction mixtures due to the restriction of the highly cross-linking particle fusion process. In this study, we prepared sub-200 nm, narrowly dispersed, highly cross-linked, and spherical latex particles using particle coagulation technology by controlling the relation between the cross-linking net formation and particle coagulation. Depending on the addition time or feeding rate of the cross-linker (divinylbenzene, DVB), the particles with different sizes or shapes were obtained. The later the addition start time of DVB, the narrower the particle size distribution of the latex particles. Alternatively, the increase of the continuing feeding time could also be used to decrease the width of particle size distribution of the ultimate latex. In addition, narrowly dispersed and spherical latex particles also could be directly obtained by advancing the particle coagulation time using 2, 2′-Azobis (2-methylpropionamidine) dihydrochloride as a cationic initiator. Our study presents a new method that will further widen the fields of application of particle coagulation technology.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）