聚醚型聚氨酯橡胶／氯丁橡胶共混物性能的研究

研究了聚醚型聚氨酯橡胶/氯丁橡胶共混物复合交联体系及其对共混硫化胶物理机械性能的影响;探讨了聚氨酯橡胶/氯丁橡胶共混胶料的硫化特性,共混硫化胶的力学性能、耐热老化性能和动态力学性能.结果表明:硫黄/MgO体系能够很好地硫化PUR/CR共混胶;当共混胶中PUR用量在0～100份范围内,共混胶的焦烧时间和正硫化时间均先减小后增加,最小转距和最大转距都降低;拉伸强度、撕裂强度和硬度均随PUR用量的增加而增加.拉断伸长率在PUR用量为40份时最大;共混硫化胶的耐热老化性能随着PUR用量的增加而增加,其拉仲强度保持率和拉断伸长率保持率呈上升趋势;动态力学研究表明,PUR和CR有很好的相容性,玻璃化温度随着PUR用量的增加而降低.     

促进剂对氯丁胶/反式-1,4-聚异戊二烯并用胶性能的影响

将促进剂TMTD、NA-22和DM用于氯丁橡胶（CR）和反式-1，4-聚异戍二烯（TPI）并用胶中，研究其对并用胶性能的影响。结果表明，与促进剂NA-22和DM相比，促进剂TMTD可以降低混炼胶的门尼粘度，提高胶料的流动性；缩短正硫化时间，有利于改善加工工艺，提高硫化效率。加入促进剂DM的胶料焦烧时间比较长，加工安全性提高，但正硫化时间过长，硫化效率低。加入促进剂TMTD的胶料拉伸强度、拉断伸长率、撕裂强度等物理机械性能优异，屈挠性能提高显著；耐老化性能略有下降。当促进剂TMTD的用量在1．0～1．3份时胶料的综合性能最好。     

硫化体系对CM/NR并用胶性能的影响

研究6种硫化体系对氯化聚乙烯橡胶(CM)/NR并用胶性能的影响.结果表明,硫黄/过氧化物并用硫化体系胶料具有合适的焦烧时间和正硫化时间以及较好的物理性能.在硫黄/过氧化物并用硫化体系中,随着硫黄用量增大,CM/NR并用胶的焦烧时间呈稍微增大趋势,正硫化时间呈现缩短趋势,同时物理性能和耐热空气老化性能等呈现不同的变化规律,当硫黄用量为0.6～1.2份时,胶料的综合物理性能较好.     

硫化剂TCY/硫黄并用硫化体系对ACM性能的影响

研究硫化剂TCY/硫黄并用硫化体系对丙烯酸酯橡胶(ACM)性能的影响.结果表明,硫化剂TCY和硫黄用量对ACM硫化胶的耐油性能影响不大;当硫化剂TCY用量为1.5份、硫黄用量为0.3份时,ACM胶料的硫化速度较快,硫化胶各项性能较好,特别是耐热空气老化性能优异.     

硫化体系对BIIR/NR轮胎内衬层胶料性能的影响

采用硫黄和酚醛树脂2种硫化体系硫化溴化丁基橡胶(BIIR)/天然橡胶(NR)轮胎内衬层胶料,研究了这2种硫化体系对内衬层胶料的硫化性能、物理性能、耐热空气老化性、耐臭氧老化性及气密性的影响。结果表明,随着硫黄和酚醛树脂用量的增加,胶料的正硫化时间(t90)缩短,硫化速度逐渐加快;硫化胶的300%定伸应力和拉伸强度增大,酚醛树脂硫化的硫化胶的耐臭氧老化性较好;透气量随硫黄和酚醛树脂用量的增加而增大,但酚醛树脂硫化的胶料的透气量要小于硫黄硫化的胶料。     

甲基丙烯酸镁对EVM硫化胶性能的影响

将不饱和羟酸金属盐与乙烯-乙酸乙烯酯共聚物（EVM）共混制备硫化胶，研究了甲基丙烯酸镁（MDMA）对过氧化物硫化的EVM的硫化特性，物理机械性能以及耐热氧老化性能的影响。结果表明，MDMA能提高EVM胶料的硫化速度；MDMA显著地提高了EVM硫化胶的物理机械性能，其用量为20-50份时，硫化胶的拉伸强度保持在20MPa以上；与高耐磨炉黑增强的硫化胶相比，MDMA增强的EVM硫化胶具有较好的耐热氧老化性能。     

硫化体系对CR/EPDM并用胶性能的影响

试验研究几种EPDM硫化体系对CR／EPDM并用胶在不同停放时间后的硫化特性和硫化胶物理性能的影响。结果表明，EPDM硫化体系采用促进剂CZ／EZ／D／硫黄并用体系，在一定停放时间内CR／EPDM并用胶的硫化速率变化不大，硫化胶物理性能与CR硫化胶相近；采用硫化剂BIPB／助交联剂TAIC／硫黄并用体系，CR／EPDM并用胶的硫化速率小，硫化胶的物理性能较差；采用促进剂BZ／M／TMTM／硫黄、促进剂BZ／M／TRA／硫黄或促进剂DM／D／TMTD／硫黄并用体系，胶料停放时间过长会使CR／EPDM并用胶的硫化速率明显减小，且硫化胶的耐热老化性能较差。     

硫化体系对燕化EPDM中试产品性能的影响

研究了硫黄硫化体系和过氧化物体系对燕化中试产品三元乙丙橡胶(EPDM)性能的影响。实验结果表明,硫黄硫化体系中硫黄用量为1.5份时胶料物理机械性能最好;硫黄用量为2份时,胶料耐热老化性能最好。硫黄硫化体系中,二硫化四基秋兰姆(TMTDM)、2硫醇基苯并噻唑(M)和N-环己基-2-苯并噻唑次磺酸胺(CZ)3种促进剂并用时协同作用较好,胶料硫化速度最快,力学性能最好;促进剂TMTD用量为1.5份时,胶料压缩永久变形最小,耐热性能最好。过氧化物硫化体系中,当DCP用量由2份增加至5份时,胶料硫化速度提高,力学性能下降,压缩永久变形性能有一定改善。三烯丙基异氰脲酸酯(TAIC)用量为5份时,胶料压缩永久变形最小,耐热氧老化性能最好。     

杜仲胶/天然橡胶/顺丁橡胶并用胶的工艺研究

用杜仲胶(TPI)替代部分天然橡胶(NR),并与顺丁橡胶(BR)共混生产出混炼胶,研究了TPI/NR/ BR共混硫化胶料制备过程中,硫化温度、硫化时间、硫化剂的用量、硫化促进剂的种类及用量对胶料物理机械性能的影响。研究结果表明,硫化过程中当硫化温度为150℃、硫化时间为20 min、硫化剂为硫黄(质量不超过3份)和硫化促进剂的含量为2份时,胶料的综合物理机械性能较好。     

硫黄/DCP并用硫化体系对NR胶料抗硫化返原性能的影响

研究硫黄／DCP并用硫化体系对NR胶料抗硫化返原性能、硫化胶物理性能及耐热老化性能的影响，并与相应的平衡硫化体系进行对比。结果表明，在NR硫黄硫化体系中加入1～2份硫化剂DCP，当硫化温度低于160℃时，胶料的抗硫化返原性能与相应的平衡硫化体系胶料相当；随着硫化温度的升高，胶料的抗硫化返原性能下降；对硫化胶的综合物理性能无不良影响，可略提高硫化胶的耐热老化性能。     

Full characterization for material constants of a promising KNN-based lead-free piezoelectric ceramic

Potassium-sodium niobate (K_1-xNa_xNbO₃, referred to as KNN) solid solutions, which are an important type of lead-free piezoelectric materials possessing environmentally friendly features, good piezoelectric response and high Curie temperature, have attracted considerable attention in replacing lead-based ceramics. In order to promote the application of KNN-based ceramics in piezoelectric devices, we characterized a complete set of material constants of a high performance KNN-based ceramic, that is 0.965(K_0.48Na_0.52) (Nb_0.96Sb_0.04)O₃-0.035Bi_0.5Na_0.5Zr_0.15Hf_0.75O₃ (KNNS-BNZH), whose Curie temperature is 235 °C, piezoelectric coefficient d₃₃ is 380 pC/N and electromechanical coupling factor k₃₃ is 70%. These results will benefit the design of piezoelectric transducers and actuators using lead-free piezoelectric ceramics.     

Investigation of dielectric and piezoelectric properties in aliovalent Eu3+-modified Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics

Rare earth (Eu³⁺)-modified Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) polycrystalline ferroelectric ceramics were fabricated by high-temperature solid-state sintering, the phase structure, dielectric and piezoelectric properties were investigated. Eu³⁺ addition was found to significantly improve dielectric and piezoelectric properties of PMN-PT, where the optimized properties were achieved for the composition of 2.5 mol%Eu: 0.72PMN-0.28PT, with the piezoelectric d₃₃ = 1420 pC/N, dielectric ε_r = 12 200 and electromechanical k₃₃ = 0.78, respectively. All these results indicate that the Eu³⁺-doped PMN-PT ceramics are promising candidates for high-performance room-temperature piezoelectric devices.     

Mechanical,dielectric, and thermal properties of fluorosilicone rubber composites filled with silica/multiwall carbon nanotube hybrid fillers

In this work, hybrid fillers consist of modified silica (SiO₂) and multiwalled carbon nanotube (MWCNT) were used to improve the mechanical, dielectric, and thermal properties of fluorosilicone (FSR) composites via a direct mechanical mixing method. With the increase of CNT loading in SiO₂/CNT hybrid loading ratio, the tensile properties, dielectric constant, electrical conductivity, and thermal properties all increase without a sharp sacrifice of flexibility. The dielectric constant of FSR-S15/C5 achieved 7,370 @1 kHz, which is about four orders of the FSR-S20, and the dielectric loss remains as low as 0.676 @1 kHz. Therefore, the linkage of SiO₂ and FSR chains not only enhances the interfacial interaction between the fillers and FSR matrix but also decreases the agglomeration of the fillers in matrix. What is more, modified SiO₂ and CNT were designed as the effective hybrid filler to improve the performance of the polymeric matrix through synergic effect.     

High magnetic and ferroelectric properties of BZT-LSM multiferroic composites at room temperature

In this research, the effects of La_0.7Sr_0.3MnO₃ additive on the phase evolution, microstructure, dielectric, ferroelectric and magnetic properties of BaZr_0.07Ti_0.93O₃ ceramics were systematically investigated. The (BaZr_0.07Ti_0.93O₃)/x(La_0.7Sr_0.3MnO₃) or BZT/xLSM (where x?=?0, 5, 10 and 20?mol%) ceramics were prepared via a solid state reaction method. A pure perovskite phase is observed for the samples of x?≤?10?mol%. The M-H hysteresis loops also show an improvement in the magnetic behavior for higher LSM content samples as well as the modified ferroelectric properties. However, the 5?mol% sample exhibited the optimum ferroelectric and ferromagnetic properties with remnant magnetization (M_r) and remanent polarization (P_r) of 2.38?emu/g and 10.5?µC/cm², respectively. The dielectric-temperature curves show that the two phase-transition temperatures as observed for the unmodified BZT ceramic merges into a single phase-transition temperature for the 5?mol% sample and then become flat curves for the 10?mol% sample. In addition, the mechanical properties i.e. Knoop hardness and Young's modulus values increase with increasing LSM content, where Knoop hardness and Young's modulus values for the 20?mol% sample are increased by ~ 45% and ~ 104%, respectively, as compared to the unmodified sample.     

PVDF piezoelectric voltage coefficient in situ measurements as a function of applied stress

Direct piezoelectric g₃₁ voltage coefficient was measured in situ as a function of applied tensile stress for films of polyvinylidene fluoride (PVDF). Measurements were performed under quasi‐static conditions with applied strain rates of 0.5–1.5 mm/min for strains up to 12%. Open‐circuit voltage was measured with a contact‐less electrostatic voltmeter. Obtained results show a strong dependence of the g₃₁ coefficient of mono‐oriented PVDF films on the applied stress, with a maximum value of the coefficient in the transition region between elastic and plastic deformation zones. The effect of sample geometry on the apparent g₃₁ coefficient is shown and discussed. The anisotropy of the piezoelectric effect is studied by means of g₃₁ and g₃₂ measurements. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43248.     

A methacrylate monomer bearing nitro,aryl, and hydroxyl side groups: Homopolymerization,characterization, dielectric,and thermal degradation behaviors

2‐Hydroxy‐3‐(4‐nitrophenoxy)propyl methacrylate (HNPPMA) monomer was synthesized. The poly(HNPPMA) was prepared by free radical polymerization (FRP) method. The characterization of poly(HNPPMA) was carried out using FT‐IR, NMR, differential scanning calorimetry, and GPC techniques. The thermal stability and degradation behavior of this polymer have been studied by using thermogravimetry (TG), GC‐MS, NMR, and FT‐IR. The results were in comparison to poly[2‐hydroxy‐3‐(1‐naphtyloxy)propyl methacrylate] sample with α‐naphtyloxy side group prepared by the same method in the our previous study. The effect of thermal activation on non‐isothermal decomposition kinetics of poly(HNPPMA) was investigated using thermogravimetric analysis according to Flynn‐Wall‐Ozawa method. The dielectric measurements of poly(HNPPMA) and doped with europium(III)chloride (EuCI₃) were investigated by impedance analyzer technique in range of 10–4000 Hz frequency by depending on the alternating current conductivities. The mode of thermal degradation including formation of the main products of poly(HNPPMA) degraded from ambient temperature to 500 °C was identified. S°, the cold ring fraction (CRF) was collected from room temperature to 500 °C. The structure of the degradation products has also been studied depending on the GC‐MS analysis. The thermal degradation mechanism for poly(HNPPMA) with radical degradation processes thought to dominate at high temperature was proposed based on GC/MS, NMR, FT‐IR, and taking into account the new products and differences in stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43925.     

Metallopolymers based on a polyazomethine ligand containing rigid oxadiazole and flexible tetramethyldisiloxane units

Soluble, easily processable polymer–metal complexes with improved optical and dielectric properties for optoelectronic functional materials were obtained. For this, a new polyazomethine (PAZ2) was prepared by the reaction of a siloxane dialdehyde and bis(formyl‐p‐phenoxymethyl) tetramethyldisiloxane with 2,5‐bis(p‐aminophenyl)‐1,3,4‐oxadiazole, and it was used as a ligand for Cu(II), Co(II), and Zn(II) ions on the basis of the presence of the electron‐donor nitrogen atoms from the azomethine group and oxadiazole ring. The structure of the PAZ2 was determined by spectral [Fourier transform infrared (FTIR) and ¹H‐NMR spectroscopy] techniques. The metal complexation was proven by FTIR spectroscopy, and the silicon‐to‐metal ratios in the complexes were established by energy‐dispersive X‐ray fluorescence. The new materials were characterized by gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. The optical properties of PAZ2 and the derived metal complexes were studied by ultraviolet–visible and fluorescence spectroscopies. PAZ2 shows fluorescence emission, and it was significantly enhanced by metal complexation. The emission was enhanced by protonation; this behavior is useful, especially for sensors. The electrical properties were investigated by dielectric spectroscopy at various frequencies and temperatures, and this emphasized the existence of dipolar relaxations. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41631.     

The effect of the Zn/Sn ratio on the formation of single phase kesterite Cu2ZnSnS4 solar cell material

The effect of the Zn/Sn ratio in the solution on the properties of Cu₂ZnSnS₄ films prepared by sol-gel method has been investigated. As the Zn/Sn ratio in the solution increases to a certain value, a pure single phase kesterite CZTS is obtained and confirmed by XRD, XPS and Raman. Through controlling the Zn/Sn ratio in the solution, secondary phases such as SnO₂ can be avoided and an optimal condition for single phase kesterite CZTS can be achieved. Surface SEM images of the CZTS films are investigated and the optical band gap of the optimized CZTS film is found to be 1.23 eV.     

γ Irradiation effects on optical,thermal, and mechanical properties of polysulfone/MWCNT nanocomposites in argon atmosphere

Polymer‐based composites find use in many nuclear and space application for their ease of fabrication, tailor made properties and light weight. Certain polymers like PTFE, unfilled polyesters and polyamides are prone to degradation in presence of high energy radiation while polymers like epoxies, polyimides, and poly‐ether ether ketone have good stability to ionizing radiation. Incorporation of fillers like carbon nanotubes (CNTs) is likely to improve the radiation resistance of the polymers. In this work, polysulfone (PSU)‐based nanocomposites were fabricated using multiwalled carbon nanotube (MWCNT) by solution mixing process. The morphology of the PSU/ MWCNT nanocomposites films were studied using Field Emission Scanning Electron Microscopy (FESEM). The prepared films were subjected to γ radiation in an argon environment (to avoid the effect of air/oxygen). Different techniques were used to understand the radiation‐induced changes. Gel Permeation Chromatography (GPC) traces of neat PSU before and after exposure to radiation shows a decrease in molecular weight. Infrared spectroscopy shows changes in chemical structure. Differential Scanning Calorimetry (DSC) thermograms reveal dose‐related changes. For neat PSU, a decrease in T_g was observed with increase in dose. For PSU/ MWCNT nanocomposites, the increase in MWCNT content and dose (up to 1.5 MGy) increased the T_g. Thermo Gravimetric Analysis (TGA) showed a marginal decrease in thermal stability for pristine PSU as well as PSU/MWCNT nanocomposites with irradiation. Tensile strength increased with increasing MWCNT content but decreased with dose. Elongation at break decreased with MWCNT content as well as radiation dose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42017.     

铅酸蓄电池用胶黏剂性能对比

为了解决阀控密封铅酸蓄电池的密封问题,通过对AB胶、3114AA、3114C的机械性能、化学性能、物理性能的对比实验,认为：AB胶在对ABS的粘接强度、固化速度方面都要优于3114AA和3114C,同时它的价格也便宜,因此,我们选用AB胶作电池盖与槽密封的胶黏剂;而3114AA、3114C在对金属铅的粘接强度、耐硫酸腐蚀方面都优于AB胶,同时3114AA较3114C具有固化时间更短、对ABS的粘接强度更高、耐硫酸腐蚀能力更强、可以常温固化等优点,因此,我们就用3114AA作电池极柱密封的胶黏剂。