英语翻译以聚乙烯醇和甲醛为原料,在水溶液中进行缩醛反应制备聚乙烯醇缩甲醛,在聚乙烯醇缩甲醛中添加适量的尿素改性,制得尿素改性后的聚乙烯醇缩甲醛胶粘剂.通过实验研究了pH值、甲

英语翻译以聚乙烯醇和甲醛为原料,在水溶液中进行缩醛反应制备聚乙烯醇缩甲醛,在聚乙烯醇缩甲醛中添加适量的尿素改性,制得尿素改性后的聚乙烯醇缩甲醛胶粘剂.通过实验研究了pH值、甲
英语翻译
以聚乙烯醇和甲醛为原料,在水溶液中进行缩醛反应制备聚乙烯醇缩甲醛,在聚乙烯醇缩甲醛中添加适量的尿素改性,制得尿素改性后的聚乙烯醇缩甲醛胶粘剂.通过实验研究了pH值、甲醛用量、反应时间、反应温度、水的加入量以及尿素用量对聚乙烯醇缩甲醛胶粘剂性能的影响.得出最佳工艺条件如下,各原料配比为：聚乙烯醇12.5 g、甲醛4.5 mL、尿素1.5g、蒸馏水87.5 mL ；反应温度为90 ℃,反应时间为3 h,反应pH值为2～2.5,所得改性后的产物聚乙烯醇缩甲醛胶粘剂粘度为7.8.0,游离甲醛含量为0.06 %.

英语翻译以聚乙烯醇和甲醛为原料,在水溶液中进行缩醛反应制备聚乙烯醇缩甲醛,在聚乙烯醇缩甲醛中添加适量的尿素改性,制得尿素改性后的聚乙烯醇缩甲醛胶粘剂.通过实验研究了pH值、甲
The polyvinyl formal (PVFO) was firstly prepared by aldolizing the raw materials of polyvinyl alcohol and formaldehyde in aqueous solution,then it (PVFO) was modified by adding urea to prepare the urea-modified polyvinyl formal adhesive.The impact of pH value,dosage of formaldehyde,time of reaction,temperature of reaction,dosage of water and amount of urea on the properties of polyvinyl formal adhesive were researched in the experiment.The optimal process conditions observed were as follows:the ratios of raw materials:polyvinyl alcohol= 12.5g,formaldehyde= 4.5mL,urea= 1.5g,distilled water= 87.5mL; the reaction conditions:temperature= 90℃,time= 3h,pH value= 2.5.The viscosity of modified polyvinyl formal adhesive is 7.6 8,and the content of free formaldehyde is 0.06%.

Using polyvinyl alcohol and formaldehyde as raw materials, in water solution response preparation of polyvinyl formal acetal, in adding the right amount of urea modified polyvinyl formaldehyde, urea w...

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Using polyvinyl alcohol and formaldehyde as raw materials, in water solution response preparation of polyvinyl formal acetal, in adding the right amount of urea modified polyvinyl formaldehyde, urea was modified polyvinyl formal adhesive. PH is studied through experiments, the dosage of formaldehyde, reaction time, reaction temperature and addition amount of water and urea dosage on the properties of the polyvinyl formal adhesive effect. Best process conditions were as follows, the ratio of raw material: polyvinyl alcohol 12.5 g, 4.5 g, 4.5 mL, urea formaldehyde, 87.5 mL distilled water; Reaction temperature is 90 ℃, reaction time is 3 h, reaction pH value is 2 ~ 2.5, the viscosity of the product of modified polyvinyl formal adhesive is 7.6 ~ 8.0, free formaldehyde content of 0.06%.

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With polyvinyl alcohol and formaldehyde as raw material to produce polyvinyl acetal by reacting in aqueous solution, by adding proper amount of urea in the polyvinyl alcohol-formaldehyde for reform, f...

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With polyvinyl alcohol and formaldehyde as raw material to produce polyvinyl acetal by reacting in aqueous solution, by adding proper amount of urea in the polyvinyl alcohol-formaldehyde for reform, finally got polyvinyl formal adhesive. Through experimental study on pH value, amount of formaldehyde, reaction time, temperature, water content, and influence of urea content on properties of polyvinyl formal adhesives. Reach optimum process conditions as follows, raw materials proportion: 12.5 g of polyvinyl alcohol, 4.5 mL of formaldehyde, urea 1.5G, 87.5 mL distilled water; the reaction temperature of 90 ° c, the reaction time is 3 hrs, the reaction pH value is 2~2.5, the final product of modified polyvinyl formal adhesive viscosity is 7.6~8.0, free formaldehyde content is 0.06%.

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Polyvinyl alcohol and formaldehyde as raw materials, was prepared by the reaction of polyvinyl formal Acetal in aqueous solution, adding urea in polyvinyl formal modified urea modified polyvinyl forma...

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Polyvinyl alcohol and formaldehyde as raw materials, was prepared by the reaction of polyvinyl formal Acetal in aqueous solution, adding urea in polyvinyl formal modified urea modified polyvinyl formal adhesive, prepared after. Through the study of pH value, dosage of formaldehyde, reaction time, reaction temperature, the influence of the amount of water and urea on the properties of polyvinyl formal adhesive. The obtained the better process condition, the ratio of raw materials: polyvinyl alcohol 12.5 g, 4.5 mL, formaldehyde urea 1.5g, distilled water 87.5 mL; the reaction temperature is 90 ℃, reaction time was 3 h, reaction pH value of 2 ~ 2.5, the modified product of polyvinyl formal adhesive viscosity is 7.6 ~ 8, the content of free formaldehyde 0.06%. 百度翻译

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