Thermodegradative and morphological behavior of composites of HDPE with surface-treated hydroxyapatite

• Published in: Polymer bulletin (Berlin, Germany) Vol. 64; no. 1; pp. 67 - 79
• Main Authors: Albano, Carmen, Cataño, L., Perera, R., Karam, A., González, G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2010; Springer; Springer Nature B.V
• Subjects: Acids; Acrylic acid; Applied sciences; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Composite materials; Composites; Copolymers; Decomposition; Exact sciences and technology; Forms of application and semi-finished materials; High density polyethylenes; Hydroxyapatite; Mechanical properties; Modulus of elasticity; Morphology; Nucleation; Numerical methods; Organic Chemistry; Physical Chemistry; Polyethylene; Polymer industry, paints, wood; Polymer Sciences; Polyolefins; Soft and Granular Matter; Stability analysis; Symmetry; Technology of polymers; Tensile strength; Thermal decomposition; Thermal stability; Thermogravimetric analysis; Degradative behavior; Mechanical behavior; Composites; Morphological behavior; Invariant kinetic parameters (IKP); HDPE/HA; Elastic modulus; Acrylic acid copolymer; Olefin copolymer; Reaction order; Acrylic acid; High density ethylene polymer; Mechanical properties; Hydroxyapatite; Dispersion reinforced material; Experimental study; Modeling; Composite material; Thermal stability; Surface treatment; Thermal properties; Kinetic model; Morphology; Ethylene copolymer; Olefin polymer; Kinetics; Activation energy
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-009-0140-1

In the present work, the thermodegradative and morphological behavior of composites of high-density polyethylene and surface-treated hydroxyapatite (HDPE/HA) were studied. Composites were prepared with HDPE, 30 wt% of HA and 2 phr of an ethylene–acrylic acid copolymer (20 wt% of acrylic acid) (EAA) and melt-blended in an internal mixer at 160 °C and 50 rpm. Two sets of composites filled with different surface-treated hydroxyapatite (STHA) were prepared: one HA sample was pretreated with ethylene–acrylic acid copolymer (STHA 1 ) and the other one with acrylic acid (STHA 2 ). Thermogravimetric analyses were carried out to evaluate the thermal stability of the composites. The activation energies (Ea) were determined using a numerical method based on the Invariant Kinetic Parameters (IKP). The thermal decomposition of the HDPE/HA composites showed an Ea value of 330 kJ/mol. On the other hand, HDPE/HA/EAA and HDPE/STHA 1 composites showed a sudden decrease in Ea (272 and 270 kJ/mol, respectively). The HDPE/STHA 2 composite exhibited an Ea value of 313 kJ/mol, slightly lower than that of the HDPE/HA composite. Additionally, with the presence of EAA copolymer and acrylic acid in the composites, the nucleation and nucleus growth kinetic-model probabilities decreased compared to those of the HDPE/HA composite. However, there was an increase in the probability of the reaction order of the model. This behavior could be attributed to the morphology of the composites and to the addition of a less thermally stable component, i.e. EAA copolymer and acrylic acid. On the other hand, due to the interaction polymer/surface-treated filler, an increase in the Young Modulus and the tensile strength was observed.