Influence of Cobalte Octoate on Degree of Cure and Flexural Strength of an Unsaturated Polyester

A r ticle ID:042727104(2007)0520749201

R 22B y R M G ,K M y ,Influence of Cobalte Octoa te on Degree of Cure an d Flexural

Strength of an U n s aturated Polyester Resin

R M G engan 1,K Moodley 2

(1.Depar tment of Chemistr y,D urba n U niv ersity of Technology,P O Box 1334,D ur ban ,4000,South Af rica ;

2.Fibreglas s Resin Company ,53Alo ef ield Crescent ,D urba n ,4001,South Af rica)

K eyw o r ds :cobalte octoate ;uns aturated poly ester resin ;DSC

CLC number :TQ 426.94

1　Introduction

In t he G R P (G lass fibre Reinforced Product )indust ry C obalt Octoate is t he promoter of choice for cross 2linki ng unsaturated polyest er (U PE)and styrene monomer.U PE ’s are oft en prepared to cont ain a concent ra 2tion of 0.04%20.05%of C obalt ions so t hat fast er cross 2linking of t he resi n is achieved and ult imat ely faster manufact uri ng of t he GRP c omponent i s achieved.These product s someti mes fail premat urely after being man 2ufact ured and dispat ched to t he end user.The influence of Cobalt Octoat e concent ration was investigated wit h respect to t he failure of t hese product s.

2　Results

Samples of t he liquid ,uncross 2linked resin c ont aini ng various c oncent rat ions of cobalt ions were prepared and t hen checked for gel times so t hat t he worki ng ti me of the resi n during manufact ure of t he G R P c ompo 2nent coul d be ascert ained.Thereaf ter four millimet er t hick castings of each sample were prepared and allowed to cure at ambient t emperat ure up to a period of t went y one days.These samples were then analyzed after t hree days and t went y one days wit h Different ial Scanning Calorimet ry(DSC)so t hat t he degree of cure c ould be est ablished for each sample.At t he same intervals ,flexural analysi s of t he same samples were determined us 2ing a mechanical tensomet er and the corresponding flexural strengt hs were evaluated.The result s indicated t hat 0.01%Cobalt ion concent ration in t he resin yielded t he highest degree of cure and flexural st rengt h after t went y one days however gel time was too long.0.05%C obalt yielded t he fast est gel ti me but fairly low de 2gree of cure and flexural st rengt h aft er t hree and twenty one days.

It is concluded that 0.01%Cobalt concent ration in t he resin is rec ommended for best cure and flexural st rength in t he end use of t he GRP component.

第46卷　第5期

2007年10月复旦学报(自然科学版)Journal of Fudan U niversity (Natural Science )Vol.46No.5Oct.2007eceived da te :20070704

iogra ph :engan oodle Corres pondence authors.