| 摘要 |
<p>The polymers are formed by heating of homo- or co-polymers (I) having residual unsaturation, at more than 200 degrees C (pref. 250 - 300 degrees C) for at least 60 min. in absence of oxygen. I may be polybutadiene or polychloroprene. The polymers I cyclise with disappearance of unsaturation giving hard and sometimes clear thermoplastics having high tensile strength, heat and oxygen resistance. The method can be used for cyclisation during moulding which alleviates handling difficulties with precyclised polymers. It is suitable for injection or extrusion moulding processes for production of films, fibres, tubes etc., and can be used in impact resistant wind shields for aeroplanes.</p> |
