Other resin systems in fiber composites

In addi­tion to poly­ester, vinyl ester and epoxy, there are a num­ber of oth­er sys­tems with spe­cial prop­er­ties that are also used to pro­duce fiber composites:

Phe­no­lic resins
Phenolic’s are par­tic­u­lar­ly char­ac­ter­ized by high tem­per­a­ture resis­tance and low-smoke, large­ly non-tox­ic fire behav­ior. Room-tem­per­a­ture cur­ing sys­tems con­tain high­ly cor­ro­sive com­po­nents that make han­dling dif­fi­cult and attack machin­ery dur­ing post-pro­cess­ing. The mechan­i­cal prop­er­ties of phe­no­lic resins are poor, and they are brit­tle and fragile.

Cyanate ester
Cyanate esters, which have excel­lent di-elec­tric prop­er­ties, are used in the man­u­fac­ture of radomes and anten­na claddings. Com­bined with fiber rein­force­ments of quartz, these resins are vir­tu­al­ly radiotransparent.

Polyurethanes
When max­i­mum tough­ness is required, polyurethanes — often com­bined with oth­er resins to increase their inher­ent­ly poor com­pres­sive strength — are the first choice. Cur­ing requires iso­cyanates, which are harm­ful to health.

Bis­maleimides
For air intakes in tur­bine engines and oth­er high-tem­per­a­ture aero­space appli­ca­tions, high tem­per­a­ture strength (250°C) is required, which is achieved by bismaleimides.

Poly­imides
At the upper end of the price scale are the poly­imides at over EUR 80/kg. They sur­pass the bis­maleimides in terms of tem­per­a­ture resis­tance; work­ing ranges up to 300°C are pos­si­ble. Some of the raw mate­ri­als from which poly­imides are made are tox­ic, so that their pro­cess­ing by hand is not rec­om­mend­ed. Pro­cess­ing is com­pli­cat­ed any­way, as water is released dur­ing cur­ing, and the strength of these resins is not very high. Their appli­ca­tion is lim­it­ed to mil­i­tary com­po­nents on mis­siles and aircraft.