1 research outputs found
Hyperbranched polymers and other highly branched topologies in the modification of thermally and uv cured expoxy resins
RESUM
Les reĂŻnes epoxi constitueixen un dels polĂmers mĂ©s emprats en el mĂłn de la industria, si bĂ© presenten una sèrie d’inconvenients, els mĂ©s importants dels quals sĂłn: la seva inherent fragilitat, la seva excessiva resistència tèrmica que en dificulta l’eliminaciĂł d’un substrat un cop finalitzada la seva vida Ăştil i l’encongiment que experimenten durant el procĂ©s de curat. Per tal de reduir o eliminar aquests problemes aquesta tesi proposa l’ús de polĂmers hiperramificats aixĂ com polĂmers estrella i copolĂmers lineal-hiperramificat de bloc com a modificants quĂmics de reĂŻnes comercials. Amb aquesta estratègia s’han aconseguit millorar la tenacitat degut a efectes flexibilitzants o a separacions de fase del modificant en la matriu epoxĂdica, aixĂ com reduir l’encongiment en el curat o la degradabilitat de les reĂŻnes, sense afectar altres propietats de la reĂŻna com la seva Tg o la seva duresa.ABSTRACT
Epoxy resins are one of the most used polymers in the field of technological applications. However, they present some drawbacks being the most important the following: they are inherently brittle materials; they present excessive thermal resistance that limits their reworkability; and the shrinkage they experiment during curing. To overcome these problems this thesis proposes the use of hyperbranched polymers, as well as star polymers and lineal-hyperbranched block copolymers as chemical modifiers of commercially available epoxy resins. With this strategy tougher materials have been obtained due to either a flexibilizing effect or a phase separation of the modifier within the epoxy matrix. Moreover, the shrinkage on curing and the degradability of the thermosets have been improved without compromising other properties of the resin such as its Tg or its hardness