Strength of Assembly Butt Joints of Plastic Pipes

The aim of the study was to compare the welded and adhesive joints made of polypropylene pipes. The pipes were butt jointed. Two pipe diameters were used: ø20 mm and ø25 mm. The welded joints were made by hot gas welding, while the adhesive joints were made by two epoxy adhesive compositions. The base for both compositions was Epidian 6 epoxy resin, which was mixed with IDA and TFF curing agents in the recommended quantitative ratios. The experimental tests consisted in determination and comparison of the strength properties of the made joints; therefore, the analyzed joints were subjected to the destructive strength tests, which determined their tensile strength in accordance with the ISO 527–1 standard. On the basis of the obtained results, it was observed that welded joints obtained the highest average strength. The lowest strength was characteristic for the adhesive joints made with Epidian 6/TFF/100:27 adhesive. The obtained results were subjected to a statistical analysis, which showed that the strength of ø20 mm diameter pipe joints did not differ significantly from the strength of ø25 mm diameter pipe joints, comparing the results for each type of joint with the assumed level of confidence α = 0.05.