丹皮酚合成工艺的改进

优化丹皮酚的合成方法,以间苯二酚为原料,通过酰基化,聚乙二醇4000为相转移催化剂与碳酸二甲酯甲基化得到的丹皮酚,收率由文献的68.3%提高到85.3%。该合成工艺反应条件温和操作简单、原料廉价易得,且用无毒的碳酸二甲酯代替剧毒的硫酸二甲酯,适合工业化生产。     

传感器用双组分加成型硅凝胶的研究

以聚甲基乙烯基硅氧烷为基胶、含氢硅油为交联剂、氯铂酸配合物为催化剂、含乙烯基的MQ树脂为补强填料、含环氧基的硅氧烷为增粘剂 ,配制加成型双组分硅凝胶 ;研究了聚甲基乙烯基硅氧烷基胶摩尔质量、交联剂的用量、催化剂的用量、MQ树脂的用量、增粘剂的用量等对硅凝胶性能的影响。结果表明 :选用粘度为 12 0 0～ 15 0 0mPa·s的基胶 ,按基胶质量计交联剂用量为 3 5 %～ 4 0 % ,MQ树脂用量为 6 0 %～ 8 0 % ,增粘剂用量为 0 9% ,铂催化剂用量 60× 10 - 6 ,可制得外观无色透明 ,硫化时间 3～ 6h、针入度大于 10 0的硅凝胶     

橡胶改性双组分丙烯酸酯胶粘剂的研究

将为克服双组分丙烯酸酯胶粘剂(SGA)韧性差、耐冲击性差的缺点,采用不同橡胶对其进行改性。以苯乙烯-丁二烯-苯乙烯嵌段共聚物SBS1401、氯丁橡胶(CR3223)、氯磺化聚乙烯CSM3305、粉末丁腈橡胶GS33为增韧剂,考查了它们对SGA胶液稳定性、黏度及力学性能的影响。结果表明,当采用CR3223、GS33时胶液稳定性较好;不同橡胶对胶粘剂的黏度影响较大;当w CR3223=6%或w CSM3305=4%或w GS33=3%时,制备的胶粘剂拉伸剪切强度较高;当w CR3223=5%或w CSM3305=3%或w GS33=4%时,制备的胶粘剂冲击强度较高。()()()()()()()()()     

水平矩形管内气液两相流界面波特性

<正>气液两相流中界面波的存在对传热、传质、阻力特性及稳定性都有很大影响。前人有关界面波的研究大多偏重于两相流中界面波的类型及其转变,而对其特征参数变化规律(如振幅、波长、频率和速度等)的研究则很少。但界面波对气液两相流流动阻力和流动结构影响机理的深入研究必须以了解界面波的各特性参数为前提,同时界面波有关特性参数的深入研究也可为气液两相流的数学理论化提供实验基础。 本文以气、水为工质,系统研究了水平矩形管内气液两相流的界面波特性。根据界面波在时域、幅域内的不同特征区别出了各种类型的波并给出了相应的波形和流型图。着重研究了界面波各特征量随气液两相流量变化的变化规律。     

针刺毡／聚酯树脂手糊层板力学性能

本文简要介绍了针刺短切玻璃毡／不饱和聚酯树脂手糊层板的力学性能。     

Silver-plated polyamide fabrics with high electromagnetic shielding effectiveness performance prepared by in situ reduction of polydopamine and chemical silvering

In this article, the silver-plated polyamide fabrics (SPPAFs) with high electroconductibility and shielding effectiveness were fabricated by using in situ reduction of polydopamine and chemical silvering. The effects of SPPAFs dopamine (C₈H₁₁O₂N) and silver nitrate (AgNO₃) concentration on surface resistivity and electromagnetic interference shielding effectiveness were studied. The results showed that the surface resistivity of SPPAFs can reach a minimum value of 0.06 ± 0.014 Ω cm⁻¹, when C₈H₁₁O₂N concentration is 4 g L⁻¹ and the AgNO₃ concentration is 120 g L⁻¹. The shielding effectiveness of SPPAFs in the wide frequency range of 10–3000 MHz increases with the increase in the concentration of AgNO₃, and increases first and stabilizes afterward with increasing C₈H₁₁O₂N concentration. When the concentration of C₈H₁₁O₂N and AgNO₃ is 3 and 120 g L⁻¹, respectively, mean shielding effectiveness values in the low-, medium-, and high-frequency bands are 71.3, 73.8, and 76.1 dB, respectively. Moreover, the mean shielding effectiveness values is 83.79 dB in the frequency range of 1.2–2.3 GHz. The dominant shielding mechanism of SPPAFs is the reflected electromagnetic waves and the absorption shielding effectiveness is less than 2 dB. The average electromagnetic shielding values of SPPAFs are above 67 dB after 16 weeks of storage, when C₈H₁₁O₂N concentration is 4 g L⁻¹ and the AgNO₃ concentration is 80 and 100 g L⁻¹. The prepared SPPAFs show promising applications in military textiles and smart wearable clothing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48227.     

3D printing hybrid organometallic polymer‐based biomaterials via laser two‐photon polymerization

Materials with microscale structures are gaining increasing interest due to their range of technical and medical applications. Additive manufacturing approaches to such objects via laser two‐photon polymerization, also known as multiphoton fabrication, enable the creation of new materials with diverse and tunable properties. Here, we investigate the properties of 3D structures composed of organometallic polymers incorporating aluminium, titanium, vanadium and zirconium. The organometallic polymer‐based materials were analysed using a variety of techniques including SEM, energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy analysis and contact angle measurements and their biocompatibility was tested in vitro. Cell viability and mode of death were determined by 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay and acridine orange/ethidium bromide staining. Polymers incorporating Al, Ti and Zr supported cell adhesion and proliferation, and showed low toxicity in vitro, whereas the organometallic polymer incorporating V was shown to be cytotoxic. Inductively coupled plasma optical emission spectrometry suggested that leaching of the V from the organometallic polymer is the likely cause of this. The preparation of the organometallic polymers is straightforward and both simple 2D and complex 3D structures can be fabricated with ease. Resolution tests of the newly developed organometallic polymer incorporating Al show that suspended lines with widths down to 200 nm can be fabricated. We believe that the materials described in this work show promising properties for the development of objects with sub‐micron features for biomedical applications (e.g. biosensors, drug delivery devices, tissue scaffolds etc.). © 2019 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Preparation of Layer-by-Layer Self-Assembled Coating Modified Polyethylene Terephthalate Fabric with Flame Retardancy and UV Protection based on ZnO Nanopaticles

A hybrid coating containing zinc oxide (ZnO) nanoparticles, polyethyleneimine and sodium alginate was fabricated on the surface of polyethylene terephthalate (PET) fabric using layer-by-layer (LbL) self-assembled method. The construction of ZnO based coating on the surface of PET fabric resulted reduced DTG peak value compared with that of pure PET. Compared with the pure PET fabric, 4 bilayers coating obviously improved the fire resistance of PET fabric, as evidenced by the obvious reduction (39%) of peak heat release rate. UV transmission intensities of ZnO coated PET fabrics are lower at 320–400 nm than that of pure PET fabric.     

Modeling of Groundwater Contamination by Phenol Released from Spilled Bitumen

Leaching of phenol from spilled bitumen into flowing aquifer poses an environmental threat to groundwater contamination. A two‐dimensional model with de‐coupled transfer was built to model phenol propagation in the flowing stream. The model predicted that the produced phenol concentration monitored at an observation well would rise sharply and then decline gradually as the phenol flux emerging from the bitumen surface was depleted with time. The model is useful in estimating the size of the spill, produced phenol concentration, phenol spatial distribution and the time required for the phenol concentration to decline to an environmentally acceptable level. It is well suited to other water pollution problems with chemical spills.     

汽车高位制动灯盖板大型注塑模具设计

针对汽车制动灯盖板的结构特点和技术要求,设计了一副热流道大型注塑模具.通过采用一种新型的交叉辅助杆斜顶抽芯结构,成功解决了大角度斜向抽芯脱模难题.通过采用热流道和圆弧潜伏式浇口,提高了塑件尺寸精度和外观质量.通过采用油缸顶出和复位的方式,保证了塑件顶出平衡和模具复位安全可靠.通过采用网格式立体冷却系统,成型周期缩短至3...