Synthesis and Characterisation of Branched Poly(ethylene terephthalate)

✍ Scribed by Rosu, Ruxandra F.; Shanks, Robert A.; Bhattacharya, Sati N.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 387 KB
• Volume: 42
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199703)42:3<267::aid-pi712>3.0.co;2-z

✦ Synopsis

Branched poly(ethylene terephthalate)s (PET) were synthesised with a variety of molar masses and with a large range of degree of branching by introduction of mono-, tri-(glycerol) and tetra-functional (pentaerythritol) comonomers to dimethyl terephthalate and ethylene glycol. The monofunctional alcohols, dodecanol and benzyl alcohol, were used as terminating agents to minimise gelation. The e †ect of various reaction parameters, such as percentage glycerol or pentaerythritol and polymerisation time, on limiting viscosity number [g] and weight average molar mass were investigated. The thermal behaviour (M 1 w ) of branched PET was studied by di †erential scanning calorimetry ; all samples showed a characteristic double endothermic melting peak and the glass transition temperature was not observed. Some branched PETs were subjected to solid-state polymerisation to increase the molar mass of previously prepared branched polymers. The solid-state polymerisation technique showed that the process not only promoted the molar mass but, more importantly, it increased the crystallinity of the polymer. Overall, the solid-state reaction rate was governed by initial molar mass, crystallinity, reaction temperature and time.