tailieunhanh - Thermal Properties of Green Polymers and Biocomposites Part 8

Tham khảo tài liệu 'thermal properties of green polymers and biocomposites part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 6 PCL DERIVATIVES FROM SACCHARIDES CELLULOSE AND LIGNIN 1. POLYCAPROLACTONE DERIVATIVES FROM SACCHARIDES AND CELLULOSE Saccharide- and cellulose-based polycaprolactone PCL derivatives are obtainable by grafting PCL chains to the OH group of saccharides cellulose and cellulose acetates having a degree of substitution DS below 3. Saccharide-based PCL s 1 have been synthesized by the polymerization of e-caprolactone CL which was initiated by each OH group of glucose fructose and sucrose. The amount of CL was varied from 1 to 5 moles per OH group of each saccharide. The polymerization was carried out for 12 hr at 423 K with the presence of a small amount of catalyst dibutyltin dilaurate DBTDL . U - CO CII 5O Figure 6-1. Schematic chemical structure of sucrose-based PCL s. 218 Chapter 6 Figure shows the schematic chemical structure of sucrose-based PCL s. The results of the characterization of glucose- Glu- fructose- Fru- and sucrose- Suc- based PCL s have been reported elsewhere 2 . Polycaprolactone derivatives from cellulose acetate CA Cellulose acetate CA - based polycaprolactone derivatives CAPCL s were synthesized from CA which was commercially obtained from Kodak Co. Ltd. The specifications of CA were as follows acetyl content Mw x 104 Mw Mn . Distilled CL which was dehydrated in benzene by reflux method was added to dried CA and polymerization was carried out for 22 hrs at 423 K with the presence of a small amount of DBTDL. CL OH mol mol-1 ratios were varied from 2 to 20 mol mol-1 CL OH ratio 2 5 8 10 15 20 . When the samples with CL OH ratio of 2 and 5 were synthesized N-methyl-2-pyrorydone was used as a solvent in order to make the reaction go smoothly. When CL OH ratio was over 8 it was unnecessary to use pyrorydone since CL itself worked as a solvent of CA. The obtained CA-PCL s were dissolved in hot acetone and then put in methanol dropwise in order to precipitate purified CA-PCL s. Precipitates in flake shape were obtained. .

TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.