3100 mm×7500 mm耐热振动筛用篦板铸件的试制

铬锰氮钢铸件,是冶金企业生产烧结矿用烧结机中的易损重要备件.篦板品质直接关系到烧结矿生产正常运行.由于铸件的制造过程中,钢液冶炼和铸型制作都存在相当难度,因采取严控钢液熔炼,改进砂型制造工艺等措施而获得成功.     

含水量对渠道保温板保温耐久性的影响及保温板厚度设计

北方渠道大多使用保温板防止混凝土衬砌受冻胀破坏。在计算保温板厚度时为了降低成本,容易忽略保温板使用过程中受各种因素的影响导致保温效果变差的情况,使混凝土衬砌达不到设计使用年限便提前被破坏。内蒙古河套灌区试验结果表明,由于受酸雨、冻融作用、含水量等因素的影响,保温板保温效果平均每年降低0.9℃,其中受含水量变化的影响最大。经试验测得:聚苯乙烯保温板(EPS)含水量每增加1%,会导致导热系数增大5%。基于多层材料串联热阻叠加原理和热阻等效原理,对保温板厚度计算公式进行完善,并提出相应的铺设方法和施工技术要求。该设计对保温板在季节性冻土区的推广应用具有一定参考价值。     

冷中间包衬对铸坯皮下气泡的影响

对铸坯产生皮下气泡的原因进行了调查和分析。认为中间包绝热板村中的有机挥发物和残余水分是铸坯产生皮下气泡的主要原因。从中间包绝热板的配方、制造技术和装砌等方面采取改进措施，可有效减少铸坯皮下气泡。     

Selective gas transport in miscible PPO-PS blends

The permeation rates of He, CO₂ and CH₄ though miscible blends of polystyrene and poly(phenylene oxide) at 35°C are reported as a function of pressure. Sorption isotherms for CO₂ and CH₄ are also presented. By using ratios of the permeabilities of the pure gases the separation factors for the gas pairs He---CH₄ and CO₂---CH₄ can be estimated. For both pairs the estimated separation factor goes through a prominent maximum, thus indicating that these blends are more permselective than expected from the behaviour of polystyrene and poly(phenylene oxide). This stems from mobility considerations rather than solubility effects and a qualitative free volume argument is proposed as an explanation. The sorption and transport data have been interpreted and correlated using the dual sorption-mobility models developed previously for glassy polymers. Since the commercial polystyrene used contained a small amount of mineral oil to improve flow behaviour, the effect of this additive on polystyrene properties was explored in some detail.     

Influence of PS‐b‐PEO diblock copolymers on the compatibility of syndiotactic polystyrene modified epoxy blends

Homogeneous solutions of syndiotactic polystyrene (sPS) in diglycidylether of bisphenol A (DGEBA), containing 2.5, 5 and 7.5 wt % of thermoplastic with or without 0.5 and 1 wt % of poly(styrene‐b‐ethylene oxide) (PS‐b‐PEO) block copolymer, were polymerized using a stoichiometric amount of an aromatic amine hardener, 4,4′‐methylene bis (3‐chloro‐2,6‐diethylaniline) (MCDEA). The dynamic‐mechanical properties and morphological changes of sPS‐(DGEBA/MCDEA) compatibilized with different amount of PS‐b‐PEO have been investigated in this paper. The addition of the block copolymer produced significant changes in the morphologies generated. The size of the dispersed spherical sPS spherulites does not change significantly, but less spherulites of sPS appeared upon network formation in the systems with compatibilizer, what means that addition of compatibilizer in this system delayed crystallization of sPS in sPS‐(DGEBA/MCDEA) systems and change phase separation mechanism from crystallization‐induced phase separation (CIPS) and reaction‐induced phase separation (RIPS) almost only to RIPS. Moreover, PS‐b‐PEO with higher molecular weight of PS block seems to be a more effective compatibilizer than one with lower molecular weight of PS block. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 479–488, 2006     

Particle-Substrate Collisions, Particle Rebound and Removal

Recent progress in particle capture and rebound and its effect on the adhesion force is reviewed in this paper. Particles rebound when the incident velocity is greater than a characteristic critical velocity. Lower impaction velocity particles experience elastic and plastic deformation. Recent models for particle rebound and capture are discussed and evaluated in terms of their restrictive assumptions and results. Recent experimental data of particle rebound and capture is also discussed, as is the hydrodynamic removal of captured particles. The removal of particles occurs when the applied hydrodynamic removal force overcomes the adhesion force. The effect of adhesion-induced deformation on the removal of particles is introduced and discussed.     

积层线路板用液态感光成像油墨的应用研究

研究了积层线路板油墨的组成配方、制备和应用工艺,分析了不同预烘时间对油墨分辨率的影响以及过显和显影不足问题的形成,并从生产和实际操作的角度,提出了解决的方案。利用聚苯醚改性的环氧树脂,应用于油墨的配方中,改善了油墨固化后绝缘材料的耐热性、介电性等主要性能。油墨中改性环氧树脂的质量分数为13.0%时,固化后绝缘材料的玻璃化温度可达184.22℃,介电常数为3.19,介质耗损因数为0.019,可以作高频积层线路板的绝缘层。     

超细聚苯乙烯(PS)树脂的制备工艺研究

采用O/W型苯乙烯微乳液体系,研究了乳化剂OP-10、助乳化剂DBS、交联剂DVB等对聚苯乙烯(PS)粒径分布的影响,基于正交试验,找出了量佳微乳液体系配方。采用激光粒度仪与透射电镜(TEM)对纳米PS粒子的粒径进行了测量研究,结果表明:交联PS粒子单分散性好,大小较均匀。     

Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

The reactive compatibilization of syndiotactic polystyrene (sPS)/oxazoline‐styrene copolymer (RPS)/maleic anhydride grafted ethylene‐propylene copolymer (EPR‐MA) blends is investigated in this study. First, the miscibility of sPS/RPS blends is examined by thermal analysis. The cold crystallization peak (T_cc) moved toward higher temperature with increased PRS, and, concerning enthalpy relaxation behaviors, only a single enthalpy relation peak was found in all aged samples. These results indicate that the sPS/RPS blend is miscible along the various compositions and RPS can be used in the reactive compatibilization of sPS/RPS/EPR‐MA blends. The reactive compatibilized sPS/RPS/EPR‐MA blends showed finer morphology than sPS/EPR‐MA physical blends and higher storage modulus (G') and complex viscosity (η*) when RPS contents were increased. Moreover, the impact strength of sPS/RPS/EPR‐MA increased significantly compared to sPS/EPR‐MA blend, and SEM micrographs after impact testing show that the sPS/RPS/EPR‐MA blend has better adhesion between the sPS matrix and the dispersed EPR‐MA phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2084–2091, 2002     

低温超韧聚苯乙烯的配方研究

以高抗冲聚苯乙烯(HIPS)为基体树脂,采用双螺杆挤出机研究了不同抗冲击改性剂类苯乙烯弹性体、丙烯腈-丁二烯-苯乙烯共聚物(ABS)高胶粉、聚烯烃弹性体(POE)、丁苯弹性体、苯乙烯-丁二烯-苯乙烯弹性体(SBS)和苯乙烯-乙烯／丁二烯-苯乙烯共聚物(SEBS)对HIPS的增韧效果。结果表明,SBS和SEBS对HIPS具有最好的增韧效果,当SBS含量达到40.0份时,能使HIPS体系的常温简支梁缺口冲击强度达到42.1kJ／m~2,-40℃低温冲击强度可达25.3kJ／m~2,具有优异的低温韧性和优良的综合性能。