Adam Al-Mulla

Effect of the coupling agent on the properties of PNC-based wood/plastic composites

The increase in modulus of polypropylene (PP) upon addition of montmorillonite makes PP-based polymer nanocomposites (PNCs) ideal matrix materials for wood/plastic composites (WPCs) for decking, railing, roofing and siding applications, among others. In this work, the influence of maleated PP (that is used both as a coupling agent for WPCs and as a compatibilizer for the PNC) on increasing the modulus of extruded and injection molded PP-based WPCs is investigated. Also examined are the effects of the sequence of compounding steps and the use of different processing conditions. The improvement in mechanical properties is explained with the help of available theories and is also related to the composite morphology with the help of scanning and transmission electron micrographs.

Development and Characterization of Polyamide-10, 6/Organoclay Nanocomposites

Abstract Polyamide (PA-10, 6) with long alkane segments between amide groups was synthesized using sebacic acid and paradiaminobenzene. Organoclay was incorporated into the polyamide through the extrusion process. The structural characterizations, thermal properties, and molar mass of the polyamide nanocomposites were determined using X-ray diffraction, thermogravimetry (TG), and Fourier transform-infrared (FT-IR) spectroscopy, respectively. Tensile strength and Youngs modulus of these polymers were measured using a Universal Test Instrument. FT-IR confirmed the presence of organics in the modified clay product. Wide-angle X-ray diffraction results indicated that the nanoclay platelets were agglomerated in the polyamide matrix. Mechanical behavior and degradation kinetics of the polyamide nanocomposites are reported and discussed.

Determination of Kinetic Parameters for the Degradation of Chitosan/Silica Hybrid Nano Composites

The thermal degradation behavior of chitosan (CS) and chitosan–silica (CS–Si) nanocomposites were studied using a differential kinetic model. The influence of the heating rate in the non-isothermal degradation kinetics of CS and CS–Si nanocomposites are presented. Kinetic parameters, such as the activation energy (E) and pre-exponential factor (A), and thermodynamic parameters, such as the Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), were determined using the modified Arrhenius equation. It was shown that the rate constant for degradation (k), activation energy and pre-exponential factor depend on the heating rates. The order of reaction was found to be one. The isothermal stability of CS and CS–Si was determined from non-isothermal kinetics and was also found to be dependent on the heating rate. Thermogravimetric studies revealed that neat CS was less thermally stable than the CS–Si nanocomposites.

Development and characterization of novel polybutylene nanocomposites

Polybutylene/starch/nanoclay composite blends were prepared by melt extrusion technique. Maleic anhydride grafted polybutylene was used as a compatibilizer. The nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, rheological, and mechanical analysis. Addition of compatibilizer to the polybutylene/starch/nanoclay showed dispersion and nucleation related to the nanoclay in the polybutylene matrix. An increase in the mechanical properties like modulus and tensile strength at break and a decrease in the elongation at break were observed on the addition of compatibilizer to the matrix compared to that of uncompatibilized matrix. The biodegradability of the nanocomposites was studied using the landfill burial test. The blends subjected to the burial test were evaluated for their tensile properties. The results revealed that the tensile strength and elongation at break of the compatibilized nanocomposites decreased after 80 days of land burial test compared to the initial period.

Isothermal Crystallization Kinetics of Tricomponent Blends of Polycarbonate, Poly(Trimethylene Terephthalate) and Polybutylene Terephthalate

The isothermal crystallization kinetics of two different types of linear aromatic polyesters, namely poly(trimethylene terephthalate) (PTT), poly(butylene terephthalate) (PBT) and their blend with polycarbonate (PC) has been investigated using differential scanning calorimetry (DSC). The blend composed of PTT25/PBT25/PC50 (wt/wt.%) was synthesized using a twin screw extruder. Isothermal studies for PTT were conducted between 129 and 159 °C. The temperature ranged between 168–177 °C for PBT and between 170 and 183 °C for the blend. Avrami, Tobin and Malkin models were used to estimate the crystallization kinetic parameters, such as crystallization rate order (n), crystallization rate constant (k) and half time of crystallization (t0.5). The values of average sum of square of errors (ASE) of all models were comparable. This detailed study indicates that the models investigated are suitable for describing the crystallization kinetics of the blend and the neat polymers.