Polyester resins chopped strand mats

This is a material produced from the impregnation of glass fibre-mat (fibreglass, which is in the form of dry sheet, is commonly known as chopped stranded mat (CSM)) or rovings, with a liquid and unsaturated polyester resin, which thickens chemically to a dry sheet form. The total mix is sandwiched between polyethylene films and then roller-pressed to impregnate and consolidate it. 

Chopped strand mat. This consists of chopped strands (bundles of glass filaments) about 2 in long bound togther by a resinous binder. This type of mat is used extensively in glass-reinforeed polyester struetures. 

A polyester resin P-43 (Rohm and Haas) was selected as a matrix material. The glass fiber reinforcement was in the form of a chopped strand mat (M 700) weighing 1 Vz oz/sq ft bonded together with a high solubility polyester resin. The chopped fibers were about 2 in. long and the fiber diameter was about 0.0004 in. 

Although it might be expected that a combination of brittle reinforcing fibers and a brittle matrix (e.g., epoxy or polyester resins) would have low impact strength, this is not the case, and the impact strengths of the fibers or the matrix. For example, polyester composites with chopped-strand mat have impact strengths from 45 to 70 ft-lbf/in (94-147 kj/m ), whereas a typical impact strength for polyster resin is only about 1 ft-lbf/in (2.1 kj/m ). 

They regarded the last two as the most significant contributors to the formation of blisters in chopped strand mat (both emulsion and powder bound CSM) in polyester resins. 

Fibre reinforced plastics. The most wide-spread reinforcement is glass fibre as roving, chopped strand mat, fabric, etc. The most usual matrix materials are unsaturated polyesters and epoxy resins as thermosets. In glass fibre reinforced thermoplastics (e. g. ABS, PA, PPO), the length of the glass fibres is 1 to 3 mm. Other reinforcing fibres are aramide, asbestos, boron, carbon, etc. 

Generally the glass reinforcement used consists of chopped strand mat with a soluble polyester powder binder or chopped rovings deposited directly into the resin film. However, for certain applications woven fabrics... 

P(5) The relevant standard is ISO 2559 E-glass chopped strand mat for the reinforcement of polyester resin systems. 

Table 4.2 Property variation of polyester resins with chopped strand mats...

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