聚氨酯涂料中TDI游离单体的气相色谱分析法

聚氨酯涂料中残留的甲苯二异氰 酸单体对人体健康有害,必须加以控制。本文介绍了用气相色谱仪,氢火焰检测器,经过１０％ＳＥ－３０／ｃｈｒｏｍｏｓｏｒｂ．Ｗ．ＡＷ．ＤＭＣＳ色谱柱将涂料中残留的甲苯二异氰酸酯单体（ＴＤＩ）分离后,以正十四 作内标物,进行定量的分析方法。本方法具有快速（整个分析过程仅需７ｍｉｎ）,定量范围广（ＴＤＩ浓度最低检出为０．０１％）,对挥发性成份较复杂的样品也很适用的特点。     

聚氨酯涂料中TDI游离单体的气相色谱分析法

叙述用气相色谱仪 ,氢火焰检测器 ,经过 10 %SE - 30 /chromosorb W AW DMCS色谱柱将涂料中残留的甲苯二异氰酸酯单体 (TDI)分离后 ,以正十四烷作内标物 ,进行定量的分析方法。     

聚氨酯固化剂中游离TDI测定方法的研究

采用气相色谱法分析了聚氨酯固化剂中游离甲苯二异氰酸酯(TDI)含量.选用SE54型毛细管柱、氢火焰离子化检测器,以三氯代苯为内标物,采用较低的柱温,使内标物与TDI更好地分离,减少了副反应的发生.该方法操作简便、快速、精密度好、准确度较高,对TDI含量较低的样品,也能较好地满足要求.     

聚氨酯涂料中游离甲苯二异氰酸酯的气相色谱分析

本文采用气相色谱法测定聚氨酯涂料中的游离甲苯二异氰酸酯。样品经处理后直接进样，用氢火焰离子化检测器检测，以内标法定量，简便易行，为该组分的测定，尤其是进行多批样品的测定提供了一种可选择的方法。     

气相色谱法测定聚氨酯涂料中的游离甲苯二异氰酸酯含量

使用ＧＣ－９Ａ气相色谱仪,在１０％ ＵＣ－ Ｗ９８２／Ｃｈｒｏｍｏｓｏｒｂ 固定相上,使涂料中残余的甲苯二异氰酸酯（ＴＤＩ） 与其中所使用的溶剂、内标物等其他成分得到较为理想的分离。采用内标法进行定量分析,并对本方法的准确度、精密度、重现性、再现性作了考察,误差和精密度均在允许范围内。在选定色谱的条件下,整个色谱分析过程仅需１０ ｍｉｎ 即可完成     

快干型低游离TDI聚氨酯固化剂

采用特定的化学助剂，通过催化聚合法一步合成快干型低游离TDI聚氨酯固化剂。分析了快干型低游离TDI固化剂对聚氨酯漆膜性能的影响，其干燥速度、消光性、附着力等性能明显优于普通型低游离TDI固化剂。     

低游离TDI聚氨酯固化剂的合成

采用催化聚合法合成了低游离TDI聚氨酯固化剂。讨论了催化剂用量，反应温度和反应时间对产品游离TDI含量的影响，中试和生产结果表明，采用该方法可以明显降低产品的游离TDI含量，并且对产品的其他性能没有明显影响。     

低游离甲苯二异氰酸酯(TDI)的聚氨酯固化剂合成研究

使用催化聚合法合成了无害、低游离甲苯二异氰酸酯(TDI)的聚氨酯固化剂;并且通过正交试验确定了催化过程的最优反应条件。测试结果表明:W2030-低分子醇混合体系加入反应体系后,明显降低了预聚体中的游离TDI含量。在最优条件下合成的固化剂中的TDI残留量均低于0.5%;同时还通过动力学计算了催化聚合体系的活化能,并与TDI-TMP反应体系活化能作了比较,得出的结果表明TDI-W2030-低分子醇混合体系相对于TMP-TDI反应体系有较低的活化能,有利于制备低游离TDI的固化剂。     

聚氨酯预聚物中游离TDI的分离方法

综述了聚氨酯固化剂中游离异氰酸酯单体的分离方法，这些方法包括化学反应法、分子筛吸附法、萃取法、薄膜蒸发法。介绍每一种方法的研究现状，并主要针对薄膜蒸发法的研究给予介绍和评述，综合分析所有的方法，提出分离异氰酸酯最合适的办法是采用薄膜蒸发器进行分离，并针对薄膜蒸发器进行顺利分离提出了一些看法。     

涂料中游离甲苯二异氰酸酯测定不确定度分析

采用气相色谱内标法测定溶剂型木器涂料中游离甲苯二异氰酸酯（TDI）质量分数,对整个测量过程的不确定度来源进行了分析,建立了其测量结果不确定度的数学模型,并对不确定度的各个分量进行评估和合成,最终得到了测量结果在95％置信区间的扩展不确定度.结果表明：校正因子、重复性测量积分面积是影响游离TDI质量分数测定结果的主要原因.     

基于PTMG-TDI的低游离TDI浇注型PU弹性体的制备与性能研究

以四氢呋喃均聚醚和甲苯二异氰酸酯为原料,采用分子蒸馏法合成PU预聚体,以3,3′-二氯-4,4′-二氨基二苯甲烷为扩链剂制备低游离甲苯二异氰酸酯浇注型PU弹性体,并对其性能进行研究。结果表明,与常规PU预聚体与扩链剂的混合体相比,低游离PU预聚体与扩链剂的混合体具有良好的流动性和较快的固化速度;低游离PU弹性体与常规PU弹性体拉伸强度和撕裂强度相差不大,但前者回弹值较大、压缩永久变形较小、动态性能较好。     

降低聚氨酯固化剂TMP-TDI中游离TDI的方法研究

由三羟甲基丙烷(TMP)和甲苯二异氰酸酯(TDI)加成反应得到的聚氨酯固化剂,在常温或低温交联固化成膜,所得涂膜具有高光泽、高硬度、耐水、耐油、耐溶剂及耐酸碱等优点,但不足之处是加成反应剩余的游离TDI含量高达2%～5%,严重影响人们的身体健康。本文采用化学方法转化游离TDI,向待处理的TMP-TDI固化剂中加入定量对甲氧基苯甲醇,以使游离TDI与加入的含活泼氢物质反应,以降低固化剂中游离TDI的含量。     

聚氨酯涂料中游离TDI的毛细管气相色谱分析

建立了用毛细管气相色谱法测定聚氨酯涂料中游离甲苯二异氰酸酯（TDI）含量的方法。采用DB-5毛细管柱、氢火焰离子化检测器,在分流比为40：1、气化温度、柱温和检测器温度都为150％的条件下,溶剂、内标物、游离TDI的峰形和分离效果好,分析时间短。采用内标法进行了定量分析,对方法的回收率和精密度进行了考察。分析结果表明,采用该法的平均回收率为97．2％～100．7％,相对标准偏差为1．6％-2．5％,且该方法快速、精确,用于实际样品的测定,结果令人满意。     

Isophorone diisocyanate in blocking agent free polyurethane powder coating hardeners: analysis, selectivity, quantumchemical calculations

Blocking agent free polyurethane powder coating formulations are emission free and thus comply with the highest ecological requirements. In addition the resulting coatings exhibit an excellent performance in non-yellowing light-stable applications for exterior use. Essential component of the formulations is isophorone diisocyanate (IPDI)-uretdione, an internal blocked derivative of IPDI. For the first time it is now possible to identify each of the 10 isomers by ¹³C-NMR-spectroscopy. This opportunity leads to fundamental conclusions concerning the selectivity of IPDI in the uretdione generating step and the reactivity of the different uretdione isomers in the crosslinking reaction. Quantumchemical calculations confirm the experimental results.     

A recycling model of excess toluene diisocyanate isomers in the preparation of polyurethane prepolymer

Reaction kinetics of dropwise addition of trimethylolpropane (TMP) to toluene diisocyanate (TDI‐80) at various temperatures and initial stoichiometry was studied. The progress of the polymerization reaction was monitored by measuring the concentration of isocyanate groups and TDI isomers by means of backtitration and high performance liquid chromatography (HPLC), respectively. The kinetics of dropwise addition method, compared with the conventional one‐shot method, was well described by a second order equation. This procedure was optimized by comparing the deviations between experimental data and theoretically calculated data. The effects of temperature, initial stoichiometry and TDI isomers on the amount of excess 2,4‐TDI and 2,6‐TDI were investigated. Three commercially available TDI mixtures, 65 : 35, 80 : 20, and 100 : 0 ratio of 2,4‐TDI/2,6‐TDI, respectively, were used. A recycling model of unreacted TDI isomers and solvent was established to reach a stable process and yield polyurethane prepolymer with good reproducibility. This model has been applied in the chemical plant to prepare polyurethane prepolymer with precisely defined chemical compositions in a continuous process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2451–2458, 1998