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首次报道了硫脲甲醛聚合反应中的半结晶沉淀现象.定量分析结果显示硫脲甲醛之间的聚合反应接近一种线性交替共聚反应过程.红外光谱的结果证明不同硫脲甲醛物质的量比反应条件下产物中始终存在较强的N—H特征振动吸收峰(v=3311cm-1,δ=1541cm-1).当甲醛用量较高和硫脲用量增加时分别在1008和1137cm-1处检测到较强的C—O—C和C=S伸缩振动吸收峰.结合XRD和核磁共振分析结果推测:硫脲甲醛聚合产物中存在着一种氢键导向型结晶结构;分子中含有醚键的聚合产物因具有复杂的氢键作用没有结晶性.扫描电镜分析显示较高硫脲用量反应条件下生成了层状半结晶碎片产物,而高甲醛比例条件得到的产物为细小的层状碎片交联聚集成的球形粒子.
For the first time, the phenomenon of semicrystalline precipitation in the polymerization of thiourea was reported. The quantitative analysis showed that the polymerization reaction between thiourea and formaldehyde was close to a linear alternating copolymerization. The results of IR showed that the ratio of the amount of different thiourea formaldehyde was higher than that of the reaction (V = 3311cm-1, δ = 1541cm-1) .It is found that when the amount of formaldehyde is high and the amount of thiourea is increased, it is detected at 1008 and 1137cm-1, respectively To strong C-O-C and C = S stretching vibration absorption peak.Combined with XRD and NMR analysis results speculated that: thiourea formaldehyde polymerization product exists in a hydrogen bond-oriented crystal structure; molecules containing ether bond The polymerization product had no crystallinity due to the complex hydrogen bonding. SEM analysis showed that the layered semicrystalline fragments were formed under the higher thiourea loading conditions, and the products with high ratios of formaldehyde to the fine crosslinked layers Agglomerated spherical particles.