The use of the three-dimensional (3D) printing technique is gaining popularity due to its ability to produce products with minimum waste. 3D printing can be used to add polymers onto woven fabrics to produce novel structures. This research work concentrated on the study of the fabric properties affecting the adhesion of Polylactic Acid (PLA) polymer onto selected fabrics. Different fabrics made from cotton, polyester and acrylic, were selected and using 3D printing, PLA polymer was printed onto the fabric surface. Regression models were used to study the effect of selected fabric properties on the adhesion of PLA polymer onto the woven fabrics. The results obtained in this research work indicated that fabric areal density, warp count (Tex), weft count (Tex), fabric thickness and fabric handle indicated a positive correlation with adhesion of PLA onto woven fabrics. On the other hand, warp ends/inch and weft picks/inch showed a negative correlation with the adhesion of PLA polymer onto woven fabrics.

Textile materials have been combined with polymers using 3D printing technology, thus producing structures with novel properties. The aim of this study was to use statistical methods to determine the effect of 3D printing machine parameters on the mechanical properties of cotton fabrics combined with polylactic acid. Polylactic acid was printed on a cotton fabric using an Athena Fused Deposition Modelling 3D printer. The effect of extrusion temperature, printing speed, fill density and model height on adhesion force before and after washing was investigated. A study of the tensile strength was also undertaken using a central composite rotatable design and regression analysis. The experimental data were used to develop regression models to predict the properties of the cotton/ polylactic acid structures. The model for adhesion force before washing yielded a coefficient of determination (R2) value of 0.75 and an optimum adhesion force of 50.06 N/cm. The model for adhesion force had an R2 value of 0.84 and an optimum adhesion force of 42.91 N/cm and showed that adhesion force reduced after washing. Adhesion forces before and after washing were both positively correlated to extrusion temperature. However, they reduced with an increase in printing speed and model height. A positive correlation exists between tensile strength and temperature, while a negative correlation exists between tensile strength and printing speed and model height. From the results of this study, it was concluded that 3D printing parameters have an effect on the properties of the structures.

Composites are gradually becoming an integral material for structural and manufacturing processes. Sisal fibre has the potential to be one of the leading reinforcement natural fibres, not only in Zimbabwe, but the world over for use in glass composites. This is mainly due to it being inexpensive, exhibiting a low density, high specific strength, a high stiffness to weight ratio, non-toxicity, its abundance in Zimbabwe and its renewability. With an aim of coming up with a composite for partition board applications in the construction industry, five samples of sisal-glass composite were prepared with varying sisal fibre content and different layering techniques. Sisal fibres were pre-treated with 20% NaOH to enhance their crosslinking with the resin and reduce the chemical impurities such as lignin and waxes. Mechanical (flexural test, hardness, and tensile strength) and physical tests (density and water absorption) were conducted to analyse the properties of the composite. The results showed that treated sisal fibres had a higher breaking tenacity of 33.11 g/tex which is higher than untreated fibres with a breaking tenacity of 25.72 g/tex. The best properties were obtained in the sample with 4 layers of glass and 9 layers of sisal fibres using 200 ml of resin. The composite had a tensile strength of 57.60 MPa, flexural strength of 36 N/mm2, moisture absorption of 10% and a burning rate of 9.82 mm/min. These results were then compared with those of the current partition boards in the market. It was noted that the composite was suitable for use in partition boards. Again, regarding cost, these composites are cheaper to produce at a rate of $11.33/m2 compared to the timber costing at $16/m2.

Accelerated flex fatigue testing was carried out on nylon 6.6 tire cords, under various applied tensions (stress), at standard atmospheric conditions of 65% relative humidity and 21°C. Fatigue lifetime was measured and scanning electron microscope used to investigate the nature of failure. The study concluded that there was an exponential dependence of fatigue life on stress. The mode of failure depended on the tension applied, the underlying modes being those of kink band at lower stress levels and tensile failures as the stress level increased.

A creep model that describes the creep characteristics of nylon6.6 tire materials is proposed. An equation resulting from the model was used to fit the experimental curves by nonlinear regression. The results outline a good correlation between theoretical and experimental curves.