FTIR-ATR spectroscopic, thermal and microstructural studies on polypropylene-glass fiber composites

• The functional groups in the chemical structure of the composites were identified. • The degree of crystallinity was determined by differential scanning calorimetry (DSC). • The annealing contributes to an increase in crystallinity. • The size of polypropylene spherulites was determined by optical method. This study presents the results of examinations of polypropylene-glass fiber composites. Polypropylene matrix composites containing 30% and 50% glass fiber were tested. Part of the material was subjected to heat treatment consisting of annealing. Depending on how polymeric materials are obtained, their physical and mechanical properties change over a wide range. Their understanding and interrelation between each other depend on accurate quantitative structural assessment at both the chain and elemental cell microstructural levels and the supramolecular level. FTIR-ATR technique was used to identify the characteristic functional groups present in the chemical structure of polypropylene and composites based on its matrix. Structure analysis at the supramolecular level was performed using differential scanning calorimetry (DSC) and temperature microscopic examinations. These examinations allowed for the evaluation of thermal parameters such as melting point and crystallization temperature of the polymer matrix in the composites studied. Furthermore, by analyzing the values of thermal effects determined using the DSC method, it was possible to determine the degree of crystallinity. A deeper understanding of the interdependence between the structure and properties of polymers allows to predict the characteristics of the final product and enables optimization of technological processes.