The DMA is used to determine the modulus values of the resin to associated temperatures and frequencies. The state of viscosity of the resin is also monitored through the evaluation of tan delta values.
Gel-point of a resin implies that resin matrix has transformed into an elastic gel state and can no longer flow. The viscosity shows a sudden rise to extremely high values. The time at which this state is detected marks the onset of gelation of the resin. Gel-point essentially is at the crossover of storage modulus and loss modulus since the value of storage modulus increases due to transition from fluid to a rather solid-like elastic state. 
Use of …show more content…
Some of them are briefly discussed below:
• Low cost: The fabrication procedures involved in the Vacuum assisted resin infusion process use relatively low cost equipment for the quality of composite manufactured.
• High performance light weight laminates manufactured through this process are comparable to other more expensive manufacturing methods such as Autoclave.
• Ability of the reinforcements to be handled in dry state leading to reduced exposure to resin. The laminators are thus in less risk of catching any allergic reactions to such type of resins.
• Minimal exposure of the resin to outside atmosphere significantly reduces harm to health of associated workforce. Moreover, factories producing mass quantities of composites using this method have substantially lower cost of ventilation due to lower emissions of volatiles.
• Compared to traditional hand lay-up techniques, resin infusion process lowers the manufacturing cost associated with less amount of resin required for complete impregnation and filling of voids since the complete process takes place under a vacuum