I am working in polyester/ natural fiber composite—my research work is facing this trouble.
Whetting agents (so that it sticks to the fibre and displaces the air ... hard to make work) and / or surfactants to help the air flow out. Whichever you select, it is a chemical modification to your polymer, which is why vacuum moulding is popular. If you are trying to use 100% resin without formulating it with fillers or other agents, I suggest that this is not representative of how they are used in the real world, however, it will all depend on the nature of your study.
One thing to look out for, if you are using a catalyst, typically a peroxide, make sure it is fresh and also not causing some reaction evolving a gas, some pigments or fillers can be problematic in resin. That said, some fillers can help air flow out too.
Apply an ultrasonic vibration to the part and that should help the bubbles escape.
Unnikrishnan T G monomeric styrene is probably (depending on the resin you have) a reactive diluent. Reducing viscosity of the resin system may help air bubbles to flow out. As you suggest, wetting the fibre with styrene may help the resin to wet to it, and also displace air bubbles.
As Alan Wills suggests, ultrasonic or other agitation and vibration may help the air escape, commercially something as simple as a ridged roller is often used in traditional GRP manufacture when adding fibre matt and resin to gel coat in a mould. The ridged roller helps to wet the lay up resin to the fibre matt and the air bubbles flow out.
Wetting agents, a wax, or some of the commercial BYK Chemie air releasing agents may help. Others are avialable, but these were the things I used previously when formulating for industry some years ago.
Specific defoamers for this chemistry are available from companies like BYK Chemie.
All agents or additives (as suggested above) to avoid bubble formation will cause increasing quality problems of your final product (e.g.lower tenacity/elasicity). I suggest an intensive drying of all components (
if the quantity is enough you can use an extruding process to release the bubble from the polymer
proper selection of processing techniques and reinforcements (fibers/fillers) with suitable matrix material may lead to reduced voids...
However air bubbles are unavoidable but can be reduced with repetitive experiments and proper void calculations.....
processing technique will play a vital role in controlling air bubbles...
If bubbles are at surface, you can pop the bubbles with pin. Also you can blow them out using heat gun or hair drier. Take precaution while using heat gun. Also u can use butane torch to remove trapped bubbles. If you are curing the composite at room temperature, more use of heat gun or butane torch or any other heating device for long time will cause reduce pot time. so be careful. Heat gun is good idea.
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