聚乙烯吡咯烷酮粉碎过程残留单体及其脱除方法研究

研究了聚乙烯吡咯烷酮(PVP)粉碎加工过程中残留单体N-乙烯基吡咯烷酮(NVP)升高的机理,并采用高温脱除法和动态负压脱除法对PVP粉末进行了处理,并采用高效液相色谱仪、乌氏黏度计、激光粒度仪和粉体性能测试仪等分析了不同残留单体脱除工艺对PVP粉末各项指标的影响.结果表明:动态负压脱除法可有效脱除PVP粉末中的残留NV...     

PVP(K-30)的合成工艺

以N-乙烯基吡咯烷酮（NVP）为原料,通过水溶液中聚合制备了医药级的聚乙烯吡咯烷酮PVP（K-30）。研究了引发剂、链转移剂和温度等对PVP相对分子质量和残留单体含量的影响,获得了一条适合生产实际的、操作条件温和的PVP（K-30）适宜合成工艺路线：NVP的质量分数为40%,聚合温度为75℃,引发剂为A和B复配,其中m（A）/m（NVP）和m（B）/m（NVP）分别为0.02和0.01,V（链转移剂D）/V（NVP单体溶液）为0.02,合成的PVP相对分子质量为29.8。     

NHP脱水合成PVP单体两种方法的比较研究

对羟乙基吡咯烷酮（NHP）脱水的两种不同方法——直接脱水方法与间接脱水方法进行了研究和比较,从研究结果综合考虑各方面因素可以看出,直接脱水方法优于间接脱水方法,是未来PVP单体合成方法的发展趋势。     

PVP单体的合成研究进展及其应用

聚乙烯吡咯烷酮 ( PVP)是 N-乙烯基吡咯烷酮 ( NVP)经自由基聚合而成的一类高分子精细化学品。我国有关 PVP的研究工作分为 PVP单体 NVP的合成研究和 NVP聚合及其聚合物的应用。本文详细讨论了合成 NVP的催化剂种类、合成方法及工艺路线 ,简单介绍了 NVP合成研究的发展趋势。     

聚氯乙烯树脂中残留氯乙烯单体含量测定条件对结果的影响

通过对聚氯乙烯树脂中残留氯乙烯单体含量测定条件对分析结果影响的研究，可以进一步了解称样 重量，仪器灵敏度，衰减、标准气之间的关系，减少系统误差，提高分析结果的准确度．     

聚乙烯吡咯烷酮单体的合成工艺进展及其应用

聚乙烯吡咯烷酮(PVP)是由单体N-乙烯基吡咯烷酮(NVP)在适当的条件下聚合而成的一种高分子精细化学品。介绍了单体N-乙烯基吡咯烷酮的几种合成方法和工艺路线,对PVP在医药卫生、日用化工、食品饮料、纺织印染、涂料颜料等领域的应用进行了介绍。     

γ—射线引发丙烯酰胺在交联PVP上的接枝共聚

交联的聚乙烯基吡咯烷酮(PVPP)用60Co源作γ射线辐射 ,之后在水或者二氧六环中与丙烯酰胺回流共聚。考察了接枝共聚反应工艺条件 ,如 :总辐射剂量、反应时间、反应温度、丙烯酰胺单体浓度、水反应介质中甲醇的加入量对接枝效率的影响 ,并将酰胺基转变为氨基、酰肼、N氨基乙基酰胺。这种接枝共聚物在固定化酶方面有重要的应用。     

改性低分子量高密度聚乙烯性能的研究

本工作主要探讨改性低分子量高密度聚乙烯(LMHDPE),并用于天然橡胶、丁腈橡胶的可行性。研究了共混工艺、橡塑并用比、交联体系对两种共混胶物理机械性能的影响。结果表明,当用量为5～10％时,是橡胶优良的加工助剂和添加剂。当用量在10％以上以塑代胶时,来用中温共混,S/DCP交联,能保持良好的物理机械性能。     

色谱工作站在分析聚氯乙烯树脂中残留氯乙烯单体含量的应用

将色谱工作站与传统的色谱数据处理机进行了比较,以对PVC树脂残留氯乙烯单体含量的分析为例介绍了色谱工作站的安装调试及分析情况。     

Minimization of residual monomer content of superabsorbent hydrogels via alteration of initiating system

Production of superabsorbent polymer hydrogels with minimized residual monomer content is an essential prerequisite particularly in their related hygienic, pharmaceutical, and food packaging products. Effect of two thermodissociating initiators and an innovative two‐step initiation approach on the residual monomer content of acrylic acid‐based SAP was preliminarily investigated. Ammonium persulfate (APS) and 4,4′‐azobis(4‐cyanopentanoic acid) (ACPA) were used as water‐soluble initiators for the aqueous solution polymerization. FTIR spectroscopy was used for the structural characterization. It was found that APS was more effective than ACPA, and residual monomer was determined in the range of 2200–3000 and 8900–16,600 ppm for APS‐ and ACPA‐initiated polymerization products, respectively. Residual monomer resulted from APS/tetramethyl ethylenediamine (TMEDA) initiation system was measured to be about 4500 ± 117 ppm for one step initiation. However, a two‐step initiation strategy using the APS‐TMEDA was exposed to be a very effective method to decrease residual monomer to 212 ± 6 ppm. The variation of the hydrogel properties (i.e., gel content, swelling capacity, and the residual monomer content) versus the initiator system and concentration was discussed based on the basic literature and supported by some rheological evidences obtained from rheoanalysis of water‐swollen samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

丙烯酰胺残留单体的提取及测定

采用异丙醇和甲醇的混合溶液对应用于化妆品行业的丙烯酰胺交联共聚物乳液中残留单体丙烯酰胺(AM)进行提取,得到较佳提取方案为:V(甲醇)∶V(异丙醇)=1∶1,超声30 min。并利用高效液相色谱对提取液中的AM进行测定,得出色谱条件为:流动相V(甲醇)∶V(水)=4∶96,流速1.0 mL/min,检测波长220 nm。在此色谱条件下测试回收率为99.02%~99.62%,相对标准偏差为1.44%。     

毛细管气相色谱法测定丙烯酸树脂中残余单体

丙烯酸树脂用乙酸丁酯溶解,采用毛细管气相色谱法分离树脂中的残余单体及溶剂,然后用内标法及氢火焰离子化检测器(FID)测定各残余单体的含量。该方法分离效果好,灵敏度高,操作简单,准确可靠。     

Effects of residual monomer on the degradation of DL-lactide polymer

The effects of remaining monomer on hydrolysis of poly(DL -lactide) were examined by adding different amounts of monomer to purified polymer samples. The existence of monomer in the polymerization products was found to enhance hydrolytic degradation of the polymer. A porous texture was observed on the SEM photographs of degraded materials, which led to the conclusion that the remaining monomer enabled water molecules to gain better access to the polymer matrix through this porous structure. The effects of molecular weight and chemical composition of polylactides on the hydrolytic degradation were also studied. Poly(DL -lactic acid) with higher molecular weights showed longer retention of the initial properties such as molecular weight and tensile strength. Copolymerization of DL -lactide with glycolide enhanced the hydrolysis, probably because of increased hydrophilicity of the polymers. © 1998 SCI.     

带螯合性基团水溶性单体的合成研究

以丙烯酰胺等原料合成了一种带有能与金属离子形成五元环螯合性基团的单体,通过正交实验考察了催化剂用量、原料配比、反应温度和反应时间对产物收率的影响;评价了该单体合成的聚合物的防垢率,并与马来酸酐-丙烯酸共聚物的防垢率进行了比较。结果表明,合成的最优条件为:催化剂用量为0.5%,原料配比为A∶B=1∶1.1,反应温度为70℃,反应时间为6 h。红外光谱和元素分析表明,产物为预期结构的单体,该单体合成的聚合物对硫酸钡垢的防垢率比马来酸酐-AA聚合物高很多。     

毛细色谱法测定氟碳树脂中的残余单体

介绍了粉末涂料的颜色测量与控制方法,包括颜色测量的基本知识、目测、仪器测量、配色及生产控制,详细介绍了仪器测配色流程,指出做好颜色测控工作必须把仪器测量与人的视觉评判、实践经验等充分结合起来。     

镍催化体系合成低分子聚丁二烯

研究了Ｎｉ（ｎａｐｈ）２－Ａｌ（ｉ－Ｂｕ）３－ＢＦ３·ＯＥｔ２－Ｃ８Ｈ１７ＯＨ体系合成低分子聚丁二烯,考察了Ａｌ／Ｂ摩尔比、Ａｌ／Ｎｉ摩尔比、Ｎｉ／Ｂｄ摩尔比、Ｃ８Ｈ１７ＯＨ／Ｂ摩尔比等反应条件对聚合活性及聚合产物分子量的影响。实验结果表明,该体系在Ａｌ／Ｂ比于０１５～０３０之间时,随着Ａｌ／Ｂ比的降低,聚合活性下降,聚合物分子量也降低。由于辛醇的作用,聚丁二烯的特性粘数最低可降至０５ｄＬ／ｇ。Ａｌ／Ｂ比的变化对聚合活性及聚合物分子量的影响显著,Ａｌ／Ｂｄ比、Ｎｉ／Ｂｄ比、Ｃ８Ｈ１７ＯＨ／Ｂ比对其影响不大     

Effect of residual monomer content on some properties of a poly(methyl methacrylate)-based bone cement

Through this article, the degree of polymerization attainable in a commercial acrylic bone cement based on poly(methyl methacrylate) (PMMA) was investigated by differential scanning calorimetry (DSC) and gas chromatography (GC). The results obtained revealed a marked dependence between the maximum monomer conversion and the cure temperature. Specimens for the mechanical evaluation of the cement were subjected to two different cure conditions: one set of samples was allowed to cure at room temperature and an additional set was also postcured at 140°C for 2 h. The latter thermal treatment permitted one to discard the presence of the unreacted monomer in the hardened material. The effect of the unreacted monomer on the mechanical behavior was evaluated by measuring the flexural modulus (E), the compressive yield stress (σ_y), and the fracture toughness (K_IC). Samples prepared at room temperature for mechanical evaluation contained residual monomer which acts as a plasticizer of the matrix, increasing K_IC and decreasing E and σ_y. The cure temperature and mold di-mensions influence the amount of the residual monomer in the hardened material. Thus, differences in the values of the mechanical properties measured for the same commercial formulation may be attributed to a different mold dimension used in the test. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1367–1383, 1998     

高效制备BDD单体新方法探究

BDD是重要的有机半导体材料的中间体。含有BDD单元的共轭聚合物材料在有机太阳能电池中具有重要应用。通过优化溴化反应溶剂、浓度、温度、底物当量比以及加料方式等条件,BDD单体溴化产率可达90%以上,大大降低聚合物材料成本。不仅如此,简化的后处理操作过程有效地缩短有机太阳能电池器件的能源补偿时间。     

Polyethersulfone (PES)–silver composite UF membrane: Effect of silver loading and PVP molecular weight on membrane morphology and antibacterial activity

Polyethersulfone–silver composite membranes were fabricated via a simple phase inversion method by using silver nitrate (AgNO₃) as an antibacterial agent and polyvinylpyrollidone (PVP) of molecular weight 10,000, 40,000 and 360,000 Da as dispersant in the dope formulation. The effect of AgNO₃ loading on the resulting membrane was studied using field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) techniques. The silver loss during fabrication and pure water filtration was measured using inductive-coupled plasma mass spectrometer (ICP-MS). From XPS and EDX examinations, it was observed that the resulting membrane prepared from 2 wt.% AgNO₃ and PVP of 360,000 Da exhibited high concentration of Ag mainly due to the high Ag-particle entrapment in the membrane structure. The uniform distribution of Ag particles has contributed significantly to 100% inhibition against Escherichia coli (E. coli) growth within 24 h incubation. In addition, the results of pure water filtration test showed minimum silver loss during operation, indicating better stability of membrane produced in terms of Ag-entrapment in membrane structure. Based on the findings, it can be concluded that PES–silver composite membrane with PVP of 360,000 MW offers huge potential membrane for bacteria removal and disinfection.