Removal and Utilization of Volatiles in Production of Cellulose Diacetate Plastics

doi:10.19491/j.issn.1001-9278.2020.12.008

Abstract

Abstract:

The effects of the moisture content and the plasticizer absorption rate on the devolatilization efficiency of cellulose diacetate were investigated， and the influences from the screw speed， feeding amount and screw configuration were also analyzed. The results indicated that water as a devolatilization promoter facilitated devolatilization. High plasticizer absorption was disadvantage for devolatilization. However， high screw speed， low feed rate and the use of high-barrier threaded element in front of the exhaust port were advantageous for devolatilization. The devolatilization can improve the transparency and heat stability of the products of cellulose diacetate. The composition analysis indicated that more than 60 % of volatiles were diethyl phthalate. The condensation system was designed to perform the separation of plasticizer from volatiles， realizing the recovery and utilization of diethyl phthalate.

Key words: cellulose diacetate, devolatilization, diethyl phthalate, recovery and utilization

CLC Number:

TQ352.71

XIANG Guanghui , YU Wenji . Removal and Utilization of Volatiles in Production of Cellulose Diacetate Plastics[J]. China Plastics, 2020, 34(12): 47-52.

Figures/Tables 12

Fig.1. Condensate collection flow chart

Fig.2. Comparison of devolatilization effect under different water contents

Fig.3. Comparison of devolatilization effects under different HPAs

Fig. 4. Effect of different screw speeds and feed rates on devolatilization efficiency

Fig. 5. Schematic diagram of different screw combinations

Fig.6. Comparison of product brightness and light transmittance at different devolatilization rates

Fig.7. Toque?time curves at different devolatilization rates

D_V/%	转矩变化率/%
0.8	111.99
1.9	48.58
2.8	36.24
3.5	23.62

Tab.1. Torque change rate at different devolatilization rates

Fig. 8. Condensate mass spectrum

名称	含量/%	测试方法
水分	35.53	容量法
酸含量（以醋酸计）	0.05	滴定法
DEP	60.44	GC?MS
其他	3.98	-

Tab.2. Chemical composition of volatile condensate

Fig.9. Volatile separation recovery system

名称

水分/%

酸含量

（以醋酸计）/%

Tab.3. Comparison of quality between condensate and fresh DEP

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