甲基丙烯酸长链烷基酯的基团转移聚合研究

进行了甲基丙烯酸长链烷基酯（庚、辛、壬酯的混合物）的基团转移聚合．得到了具有较高分子量和转化率．分子量分布较窄的聚合产物．研究了聚合条件对产物的分子量及分布，转化率，聚合速率的影响．探讨了聚合反应动力学．认为聚合体系的非极性不利于催化剂的离解，单体较大的空间障碍使扩散困难．均是表观活化能升高和转化难以完全的原因．发现此类单体的基团转移聚合对温度的依赖性极大，本体聚合无自加速现象，容易得到较高的分子量

Rapid Determination of Nine Acrylates in Food Contact Materials by Ultra Performance Convergence Chromatography

Ultra performance convergence chromatography (UPC2) was used to establish a rapid analytical method to determine nine acrylate compounds in plastic food contact materials simultaneously. The samples were extracted with methanol, filtered through an organic membrane, and separated on an ACQUITY UPC2 HSS C18 SB column with gradient elution using a mobile phase consisting of supercritical carbon dioxide and acetonitrile. The photodiode array (PDA) detector was set at 210 nm. Experimental results showed that under the optimal conditions (column temperature, 40 ℃; and back pressure, 13.79 MPa), qualitative and quantitative analysis of the nine acrylates was completed within 4 min. Linear ranges were 0.2–100 mg/L for phenyl methacrylate (PNMA), benzyl methacrylate (BZMA) and ethylene dimethacrylate (EDMA); 0.3–100 mg/L for methacrylic acid (MAA); 0.4–100 mg/L for butyl acrylate (BTA), hydroxyethyl methylacrylate (HEMA) and hydroxyethyl acrylate (HEA); and 0.5–100 mg/L for isobutylmeth acrylate (IBMA) and benzyl acrylate (BZA). The determination coefficients (R2) of the standard curves for all acrylates were higher than 0.998 5, and recoveries obtained at high (30 mg/kg), middle (6 mg/kg) and low (0.2, 0.3, 0.4 and 0.5 mg/kg) spiked concentrations ranged from 89.3% to 109.7%, with relative standard deviations of 0.62% to 3.86% (n = 6). The limits of detection (RSN ≥ 3) were 0.05–0.15 mg/kg, and the limits of quantification (RSN ≥ 10) were 0.2–0.5 mg/kg. The proposed method identified the risk of acrylate residues in 30 batches of actual samples

Study on Reducing the Contents of Free Phenol and Formaldehyde in Phenolic Foam

［中文文摘］针对如何降低酚醛泡沫中的残余单体(游离酚、游离醛)进行了研究.考察了不同酚醛比,反应温度,碱催化剂用量对残余单体的影响;添加尿素作为甲醛捕集剂对降低游离甲醛效果明显;采用醛酚比为 2.2,反应温度为 92℃,添加少量尿素(3 g尿素/100 g苯酚),制备出游离酚为 0.09%,游离醛小于 0.1%的酚醛泡沫,且其物理化学性能与通常条件下制备的酚醛泡沫无明显差异.［英文文摘］Phenolic foam is made by heating a mixture of a resol,a liquid blowing agent,a surfactant,and an acid catalyst,which initiates a condensation reaction.Compared with rigid plastic insulation materials such as polystyrene,polyurethane,and polyethylene, phenolic foam has low smoke and flammability properties,which make it an excellent candidate for use in buildings ,ships,and aircraft with promising developments in materials and new processing techniques.However,phenolic foam contains overly high contents of f ree phenol and free formaldehyde. We carried out a series of experiment s on different conditions. Free phenol was characterized by iodimet ry ,and free formaldehyde by hydroxylamine hydrochloride method. The effect of phenol/ formaldehyde molar ratios and reaction temperature on the content s of remnant monomers was discussed. The effect of adding urea on the content s of free form aldehyde was investigated. The effect of dosage of catalyzer was discussed. Under the condition at 92 ℃, CF / CP mole ratios of 2. 2 with a little urea (3 g urea/ 100 g phenol) ,phenolic foam in which the content s of f ree phenol was 0. 09 % ,and free formaldehyde was less than 0.1 % and cont rast with phenolic foam that prepare under normal condition , the performance of physics and chemistry doesn’t obvious difference have been successfully prepared

一种具有低分子量分布的丙烯腈共聚物纺丝液的制备方法

本发明公开了一种具有低分子量分布的丙烯腈共聚物纺丝液的制备方法。本发明通过在丙烯腈单体与共聚单体的溶液聚合过程中，采用连续或间歇降温的方式来调节共聚物的重均分子量和数均分子量，从而使共聚物的分子量分布指数降低。与其它方法相比，该方法简单易行，工艺可操作性较强，利用该方法制得的丙烯腈共聚物的分子量分布指数可控制在2.3～2.8之间，这种丙烯腈共聚物溶液经过脱除残余单体和气泡后可用作高性能聚丙烯腈基碳纤维的纺丝液