An investigation into the structure and performance of a glass fibre size

Abstract

Batches of film-formers were created via emulsion polymerisation from a formulation supplied by Celanese. These film-formers were then incorporated into a formulation as supplied by St. Gobain Vetrotex which is used in industry to produce a working glass fibre size. Initial studies were undertaken to determine the location of the constituent species present in the size to produce an image of its structure. The film-former formulation was then altered to produce a range of physical properties. The performance of sizes produced from these film-formers were then investigated in the areas of clarity, film formation, wetting ability and strength. Alterations to the size formulation was then undertaken to determine whether this produced any effect in the performance of the size over some of the same areas of investigation. The conclusions drawn are listed below:• The coupling agent species present in the size formulation migrates to the glass interface of the size during drying.• A minor amount of lubricant migrates to the air interface of the size during drying.• Migration of species in the size only occurs during drying when the size is in its liquid state.• The molecular weight and particle size of a film-former is directly related to the initiator and first stage monomer concentrations respectively.• The molecular weight of a film-former does not alter the size's ability to form a continuous film if dried under suitable conditions. Film-formers with large particle sizes produce inhomogeneous films due to incomplete diffusion occurring during film formation.• The inhomogeneity of films with larger particle sizes present produces an increasingly optically active film with an increased wet-out rate.• The molecular weight and particle size of a film-former do not alter the corresponding sizes ability to wet a bare glass fibre due to the large amount of water present in the size formulation.• A size can be redistributed following successive re-wetting and drying under certain conditions.•The stiffness of a size is directly related to the molecular weight of the sizes film-former.• An inhomogeneous, discontinuous size will be formed with excessive deviation from the size formulation.• An excess of coupling agent is present in the standard size formulation.