Preparation of Photosensitive Elastomer from Liquid Natural Rubber

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ชื่อเรื่อง

Preparation of Photosensitive Elastomer from Liquid Natural Rubber

ชื่อเรื่องอื่น/ชื่อเรื่องเทียบเคียง

การเตรียมอิลาสโตเมอร์ที่ไวต่อแสงจากยางธรรมชาติเหลว

ผู้สร้าง/เจ้าของผลงาน

Uthai Lairattanakul

หัวเรื่อง

Rubber
Injection molding of rubber
Polymers--Optical properties
Elastomer

คำอธิบายรายละเอียดของเอกสาร

The original of liquid natural rubber dated back to 1923 by mechano-chemical degradation of solid natural rubber8,18. It found application in the field of adhesives5. The study of photochemical depolymerization of rubber had been carried out by MRPRA, allowing short polyisoprenic chain with carboxylic ends. Ozonolysis was another reaction that caused degradation of the rubber chain. Institut de la Recherche Applique sur les Polymeres (IRAP) in France developed a method of preparation of LNR based on oxidative degradation reaction of natural rubber in the latex state at a moderate temperature by using phenylhydrazine and oxygen system. Pautrat et al. studied influence of different parameters of oxidative degradation of natural rubber. They found that the molecular weight of LNR obtained was effected by the following parameters: amount of phenylhydrazine, rate of air flow, reaction time, and temperature of the reaction.

สรุปเนื้อหา/บทคัดย่อ

Photo-induced polymerization reaction had been widely interested by macromolecular chem- ists and technologists because of the rapid chemical reaction and the ability to be carried in solution or solid state at room or high temperature. In this work photocrosslinkable elastomers were prepared by addition reaction of photosensitive acid onto epoxidised liquid natural rubber (ELNR). ELNR was prepared by two step reactions: first natural rubber was depolymerized into liquid natural rubber (LNR) by using O2/phenylhydrazine system at 60°C, then hydrogen peroxide and formic acid were added to LNR at 55 °C to epoxidise the LNR. The addition reaction of photosensitive acid such as acrylic acid, methacrylic acid and cinnamic acid onto ELNR were carried out in CHCl3 at 80°C. The kinetic of addition reaction was followed by titration of residual acid with 0.1M KOH. The acid grafted onto ELNR was obtained by precipitation in methanol. The results showed that addition reaction of cinnamic acid was slower than acrylic acid and methacrylic acid. The increase of temperature led to slight improvement in the grafting efficiency. Furthermore, the molecular weight of ELNR had also influence on the rate of addition reaction of acid. It was found that the reaction times of low molecular weight ELNR were shorter than those of high molecular weight ELNR. Photocrosslinking study of cinnamated ELNR by ultra-violet #radiation showed the rate of photocrosslinking, as followed by IR spectroscopy, to be dependent on molecular weight, thickness and percentage of cinnamate grafted to the polymer chain.

ผู้จัดพิมพ์/สำนักพิมพ์

National Research Council Thailand

วัน/เดือน/ปีที่ผลิตเอกสาร

1993

วันที่บันทึกข้อมูล

2025-06-01

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This document is distributed under the terms of the Creative Commons Attribution 4.0 International (CC-BY-NC-ND 4.0) and copyright of the Chulachomklao Royal Military Academy

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16 leaves

ต้นฉบับ/แหล่งที่มา

Journal of the National Research Council Vol. 25, No. 2, July-December 1993, 27-42
Library and Information Center, National Institute of Development Administration

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