The ability of polymers and composites on their basis to be processed in the viscous fluid state, the choice of rational methods and technological parameters of the processes of processing are largely determined by their technological properties.
In this paper, the technological properties of thermoplastic composites based on polycaproamide (PA-6) with Ni-containing silicate filler modified with polyvinyl alcohol (PVC) or polyvinylpyrrolidone (PVP) have been investigated. The modified filler was prepared by co-precipitation of polyvinyl alcohol or polyvinylpyrrolidone and sodium liquid glass from aqueous solutions under the action of nickel chloride.
It has been established that the PA-6 melt flow rate (MFR) (19.05 g/10 min) most significantly changes during the introduction of the unmodified filler (in this case, the MFR is characterized by the lowest value - 14.51 g/10 min). The use of modified fillers increases the value of MFR compared to the unmodified, which is obviously due to the redistribution of intermolecular interactions in the PA-6 system, the filler under the influence of PVP modifier or PVA macromolecules and is 17.88 and 18.71 g/10 min, respectively.
It was found that molds of polyacroamid materials with unmodified filler exhibit higher flow sensitivity to displacement stresses, as evidenced by the greater influence of the values of strain shear on effective viscosity. Fillers that are modified PVP and PVA increase the viscosity of PA-6, but the nature of viscosity dependence on shear stress versus the non-filled PA-6 does not change. The different inclination of the molten viscosity dependence curves on the shear stress of polycaproamide materials with modified excipients, as compared to unmodified ones, indicates the presence of additional interactions between the filler modifier and the polycaproamide macromolecules. An increase in temperature contributes to a decrease in the effective viscosity of the melt filled PA-6, and the effect of shear stress is more pronounced.
It was established that the introduction of unmodified filler in PA-6 reduces the value of technological shrinkage by 8-15%. At the same time, additional heat treatment leads to an increase in the value of shrinkage of the developed composites, with its greatest impact is manifested for non-filled materials.
Based on the performed researches it was discovered that polycaproamide composites with modified silicate fillers are marked in the conditions of processing by pressure casting with increased technological compatibility between the components of the system due to intermolecular interactions with the participation of functional groups of the polymer modifier and the amide groups of PA-6
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