多壁碳纳米管分散性研究

通过对多壁碳纳米管的改性研究,寻找提高碳纳米管分散性的途径。采用NaOH对碳纳米管进行预处理,通过SEM、DSC分析表明,该处理过程对去除多壁碳纳米管中杂质和提高其分散性有积极效果。通过H2SO4和HNO3的混酸处理法与HNO3处理法的对比,知前者对碳纳米管的损失要大于后者,且通过对FTIR的对比分析,后者对碳纳米管的改性效果好于前者。TG、TEM分析表明,聚乙烯醇均匀包覆在碳纳米管表面,碳纳米管分散性较酸处理的有所改进。     

Butanol isomer separation using polyamide-imide/CD mixed matrix membranes via pervaporation

Mixed matrix membranes (MMMs) comprising polyamide-imide (PAI) and α-, β- or γ-cyclodextrin (CD) have been investigated experimentally and computationally for isomeric n-butanol/tert-butanol (n-BuOH/t-BuOH) separation via pervaporation. Consistent with molecular simulation, experimental results show that the CD inclusion ability and butanol discrimination ability are dependent on both CD cavity size and butanol molecular size. The PAI membrane incorporated with α-CD has the smallest cavity and has the highest discrimination ability for the n-BuOH/t-BuOH pair but with a low butanol flux. The mixed matrix membrane embedded with γ-CD has the lowest selectivity and the highest flux. The PAI/β-CD membrane has a comparable selectivity and flux, and exhibits preferential sorption and diffusion selectivity toward n-BuOH. A maximum separation factor of 1.53 with a corresponding flux of 4.4 g/m² h are obtained at an optimal β-CD loading of 15 wt%. Further increments in the CD content eventually lead to a decrease in separation performance because of CD agglomeration and severe phase separation. To better understand the influence of CD on the separation performance of mixed matrix membranes, SEM, FTIR and XRD have been employed for membrane characterizations. The effect of n-butanol/t-butanol ratio in the feed composition has also been studied. It is found that both flux and separation factor decrease with increasing n-butanol content in the feed. The decline is attributed to the change in total vapor pressure at the upstream and the mutual drag effect of isomeric butanol molecules.     

新型聚乙烯醇缩糠醛树脂的制备和性能研究

以聚乙烯醇(PVA)和糠醛(Fu)为主要原料,在酸性介质中通过羟醛缩合反应制得了聚乙烯醇缩糠醛,然后采用氮丙啶交联剂对聚乙烯醇缩糠醛进行改性,并对改性前后聚乙烯醇缩糠醛胶膜的力学性能、动态力学性能、热失重、耐水性和耐腐蚀性等进行了对比试验。研究结果表明,改性后聚乙烯醇缩糠醛胶膜的拉伸强度提高了29.12%,断裂伸长率提高了33.23%,储能模量由11659.25MPa增加到12750.3MPa,玻璃化转变温度提高了3℃左右,并且耐水性和耐腐蚀性都有所提高。     

PVA对防雾PE膜的防雾性能的影响

研究了ＰＶＡ对ＰＥ防雾膜的防雾寿命的影响,发现ＰＥ防雾膜的防雾寿命随ＰＶＡ加入量的增加而增加,在加入量超过一定范围时,其防雾寿命开始下降,电镜照片对这一结果予以合理的解释。力学性能测试结果表明,加有ＰＶＡ的ＰＥ防雾膜伸强度,直角撕裂强度,断裂伸长率等方面比未加ＰＶＡ的防雾膜要小,但不影响其使用性能。     

我国聚乙烯醇生产的腐蚀和防蚀技术

论述了聚乙烯醇（PVA）生产中腐蚀的特点、腐蚀介质、腐蚀类型和腐蚀现状，总结了防腐蚀技术推广应用中的一些经验。     

Optical studies of pure and gelatin‐doped poly(vinyl alcohol) films irradiated with fast neutrons

The ultraviolet (UV) and infrared (IR) spectra of pure poly(vinyl alcohol) (PVA) and gelatin–doped PVA films with concentrations (2, 5, 7, 10, and 15 wt %) were studied before and after irradiation with neutron fluences in the range of 10⁵–10⁸ n/cm². The obtained data revealed that the addition of gelatin and neutron irradiation causes structural variation in the PVA network. The analysis of the UV spectra showed that the increase of dopant concentration above 5 wt % gelatin makes the sample less resistant to a degradation effect caused by neutron irradiation. It was also found that the intensity of the band at 210 nm increases by increasing dopant concentration. Careful examination of the infrared spectra indicated that the induced percent crystallinity of the sample containing 5 wt % gelatin has more stability than the other doped samples. Neutron irradiation also results in the appearance of new absorption bands and irregular change in the absorbance of some IR bands. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1395–1406, 1999     

淀粉/PVA材料的改性研究进展

介绍了淀粉/聚乙烯醇（PVA）材料的性能，及加入交联剂、增塑剂、第三相及对改性淀粉的使用的等对其性能进行进一步优化的方法，阐明了淀粉/PVA材料的发展前景。     

On‐line acoustic attenuation spectroscopy of emulsions stabilized by vinyl alcohol–vinyl acetate copolymers: a model system for the suspension polymerization of vinyl chloride

BACKGROUND: Poly[(vinyl alcohol)‐co‐(vinyl acetate)] (PVA) copolymers obtained by partial hydrolysis of poly(vinyl acetate) are currently used as industrial stabilizers in the suspension polymerization of vinyl chloride monomer (VCM). Their molecular characteristics, mainly the average degree of hydrolysis (DH ) and average degree of polymerization (DPw ), have a major influence on the monomer droplet size and the properties of the final poly(vinyl chloride) resin. RESULTS: The average droplet size and size distribution of chlorobutane/water emulsions, as a model system for VCM/water emulsions, were studied using acoustic attenuation spectroscopy on‐line with an agitated laboratory reactor. The emulsions were stabilized by PVA with DH values between 73 and 88 mol% and DPw values between 450 and 2500. The effects of agitation speed, stirring time and concentration of the PVA copolymers were investigated. An attempt was made to correlate the interfacial tension and the droplet size. CONCLUSION: On‐line acoustic spectroscopy appears to be a suitable technique for the real‐time control of the droplet size of monomer suspensions. The advantages and limitations of the technique are outlined. The validity and the application limits of the commonly cited correlation between the droplet size and the Weber number are established for polymeric surfactant‐stabilized emulsions. Copyright © 2009 Society of Chemical Industry     

利用微波测量土水系统环保传感器的研究

土水系统的复介电常数受土水系统物理化学性质的影响，通过测量土水系统的复介电常数就可以准确的评估地质环境的变化。本文对测土水系统复介电常数的微波环保传感器做了进一步研究，并且描绘了复介电常数的测量。     

聚乙烯醇水凝胶膜的强化研究

聚乙烯醇膜于水溶胀状态经电子束辐照交联得到透明的水凝胶膜,这种材料强度较低,弱而易碎。将辐射交联水凝胶膜室温脱水,于90～160℃范围内,不同温度下恒温热处理1～2小时。DSC和X—衍射测定表明,热处理后的水凝胶膜的结晶度从25％上升至43％。力学性能测定表明,其模量和断裂强度由于水凝胶的部份结晶化而得到提高。