1991 Fiscal Year Final Research Report Summary
Comparative Study on the Degradation Behavior of Degradable Polymers under Natural Environment between Japan and China
| Project/Area Number |
02045008
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Institution | Gunma University |
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Principal Investigator |
OSAWA Zenjiro Gunma University, Faculty of Engineering, Professor, 工学部, 教授 (50008439)
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| Co-Investigator(Kenkyū-buntansha) |
LI Sanshi Shenyang Institute of Chemical Technology, Applied Chemistry Department, Lecture, 講師
LI Anton Shenyang Institute of Chemical Technology, Applied Chemistry Department, Lecture, 講師
TEN Jyunbun Shenyang Institute of Chemical Technology, Applied Chemistry Department, Associa, 副教授
SYA Shinchan Shenyang Institute of Chemical Technology, Applied Chemistry Department, Associa, 副教授
李 洙天 沈〓化工学院, 教授
KURODA Shinichi Gunma University, Faculty of Engineering, Assistant, 工学部, 助手 (60205250)
KOBAYASHI Shodo Gunma University, Faculty of Enginnering, Lecturer, 工学部, 講師 (60008448)
YANO Yumihiko Gunma University, Faculty of Engineering, Professor, 工学部, 教授 (30008510)
LI Zhu-Tian Shenyang Institute of Chemical Technology, Applied Chemistry Department, Profess
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| Project Period (FY) |
1990 – 1991
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| Keywords | Ethylene-carbon monoxide copolymer / Photodegradation / Outdoor exposure / Photodegradable polymer / Chain scission / Carbonyl content / Norrish type reaction / Formation of double bond |
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| Research Abstract |
[1]. Introduction
Ethylene-carbon monoxide (E/CO) copolymers were exposed outdoors at Choshi, Sapporo, and Naha in Japan as well as at Shenyang, Qingdao, Zhengzhou, Xining, and Haikou in China for comparative studies on their degradation behaviors under different natural environments.
[2]. Relationships between photodegradations of E/CO and different natural environments
(1) In outdoor exposure the rate of degradation differed with the total radiation of ultraviolet light at the place of exposure. Actually the degradation proceeded rapidly at each city. However, the rate of degradation was in the following order : Haikou > Xining > Choshi.
(2) The degree of degradation varied from season to season because the total radiation of ultraviolet ligt differed with each season under exposing. For an example, at Choshi the radiation in summer is 1.3 times as much as in autumn and differences in the degradation of the polymers were recognized between both seasons.
(3) Degradations of E/CO copolymers were hardly affected by natural environmental factors except for the radiation of ultraviolet light.
(4) In the first stage of irradiation main chain scission of the polymers took place predominantly and this reaction led to the remarkable lowering of the molecular weight. The rate of chain scission became faster with increasing carbonyl content. The molecular weight of an E/CO sample (CO content 2.4%) exposed outdoors for only half a day decreased to about 1/3 of the initial one.
(5) Ultimate elongation of the exposed samples fell off remarkably at the very beginning of irradiation, and it differed significantly with place to place.
(6) As the rate of degradation depended on both the concentration of the carbonyl group and the total radiation of ultraviolet light at the place of exposure, the carbonyl content in E/CO copolymers should be determined by considering the radiation of ultraviolet light.
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