E N D
Mechanical, Rheological and Thermal Properties of calcium Carbonate filled PP/LLDPE Composite Presented by: Mustafa. Abu Ghalia M. Eng: Polymer of Engineering E-mail: abughalia76@gmail.com
Introduction Polymer blends have drawn great attention in scientific research and industrial production. Polypropylene (PP) is a low-cost polymer with versatile applications, but with limited impact strength. In recent years, polymeric composites were widely used in the production of new engineering materials. It is perceived as a reflection of technological development. PP has a relatively high glass transition temperature (Tg) which is reduced its application due to its brittleness
For this reason, PP has blended with other polymers to improve the impact strength. Linear Low Density Polyethylene (LLDPE) was chosen because: • can enhance the impact strength without reducing the tensile strength and modulus to a large extent. • Similarity in chemical structure, and therefore better compatibility
Problem statements Addition of CaCO3 to PP/LLDPE has the following effects: • Increase stiffness (modulus) but reduced toughness (impact strength) • Increase the viscosity and decrease melt elasticity of the polymer. Increase thermal stability of the composites • Hence, study the mechanical, rheological, and thermal properties were important to produce a materials with balance mechanical and rheological properties
Objectives The objective of this research are: 1- To study the effects of LLDPE contents to PP on mechanical, thermal, and rheological properties. 2- To investiage the effect of CaCO3content on mechanical, thermal and rheological properties of PP/LLDPE composites. 3- To determine the effect of silane coupling agent on mechanical, thermal and rheological properties incorporating calcium carbonate into PP/LLDPE composites.
Scope of Research • The samples preparation were include the following stages: - Mechanical mixed of PP/LLDPE, Dry blends • Twin screw extruder used for produce pellets of PP/LLDPE blends . • Injection mould to study the mechanical, thermal, and rheological properties, optimal result of blends were used. • Based upon the optimum formulation. The weight ratios of CaCO3 treat by Aminopropyltriethoxy to determine the effects of mechanical, thermal, and rheological properties
Research Methodology Chart Processing Temperature 190 0C Blending PP/LLDPE Treatment of CaCO3 Coupling Agent CaCO3 Characterization Mechanical test Thermal analysis Rheological
Characterization of PP/LLDPE, CaCO3 Mechanical Properties The effect of addition of LLDPE to PP on tensile strength and impact strength of PP/LLDPE blends are measured and summarized in the figures.
Mechanical properties of PP/LLDPE at different weight ratio of CaCO3
Effect silane coupling agent on the mechanical properties of PP/LLDPE incorporate into CaCO3
Rheological Behavior Rheological properties of blends polymers are strongly influenced by several parameters such as blends ratio, shear stress, shear rate, apparent viscosity, Die swell ratio and interfacial and elasticity of blends The aim of this section is to determine the effects of calcium carbonate and (LLDPE) incorporation on rheological properties. Rheological measurements were determined by melt flow index and data acquisition of a Twin Screw Extruder.
Effect viscosity for PP/LLDPE blend ratio at 190 0C of various shear rates The figure shows decrease in viscosity led to increase of shear rate, that may attributed to the lack of matrix reinforcement with the presence of LLDPE.
Effect of CaCO3 on apparent viscosity and shear rate for PL40 Increase apparent viscosity of additional CaCO3 could be explained in terms of poor interfacial adhesion between CaCO3 and the PL40, also due to the presence of non-interactive rigid particles in CaCO3
Effect of Silane coupling agent on the rheological properties The figure below showed the decrease in viscosity due to enhance particulate dispersion of CaCO3 with 3 Aminopropyltriethoxy (AMPTES) coupling agent to PL40.
Thermal Properties The thermal characterization of PP/LLDPE blends with additional of different weight ratio of CaCO3 were estimated. 1- Thermogrovimetric analysis. The initial decomposition temperature increased with increasing CaCO3 loadings. From results it showed that the thermal stability of the composites was enhanced by the addition of CaCO3. Treated CaCO3 with AMPTES coupling agent improved the thermal stability of the compounds.
The variation of degradation temperature with different CaCO3 content is summarized in the table below
2- Differential Scanning Calorimetry (DSC) The objective of this section is to determine the effect of CaCO3, and AMPTES coupling agent on (Tc), (Tm) and crystallinity content (Xc) on PP in the blends. 1- To increase LLDPE to PP didn’t show particular variation of crystallization temperature. 2- Crystallization temperature of PL40 with (10-40% CaCO3) increase while addition of AMPTES coupling agent reduce it. 3- 3-Aminopropyltriethoxy Silane coupling agent has no effect on the melting temperature of PL40/CaCO3
Effect of CaCO3 Content on Heat Deflection Temperature of PP/LLDPE Composite
3- Dynamic Mechanical Analysis (DMA) The incorporation of CaCO3 into the PL40 matrix results in a decreased in glass temperature range especially at temperature below Tg (-10 0C).
4- Scan Electron Microscopic • SEM analyzed the morphology of the PP/LLDPE filled to 20 wt % CaCO3 particles • The result showed ternary morphology, • PP continuous phase, LLDPE in PP and CaCO3 particles in PP. • It can't distinguish between PP and LLDPE on the micrographs. • Since the miscibility of both PP-LLDPE were acceptable. • The interface between LLDPE, CaCO3 particles and PP induced • some weak points, which were unable to withstand the impact loading.
(a) (d) (b) (e) Fig : SEM micrographs of fracture surfaces: (a) I-1:PP/LLDPE/CaCO3=80/10/20(at 40 0C); (b) I-2:PP/LLDPE/ CaCO3=80/40/20(at 40 0C); (c) I-3:PP/LLDPE/ CaCO3=80/80/20(at 40 0C); (d) I-4:PP/LLDPE/ CaCO3=80/50/20(at 23 0C); (e) I-5:PP/LLDPE/ CaCO3=80/50/20(at -20 0C) (c)
Conclusions 1- LLDPE blended to PP showed a good of properties in term of impact strength and stiffness which achieved by CaCO3 filled to PL40 2- TGA analysis showed incorporation of the CaCO3 which is result in a significant improvement in the initial thermal stability 3- Addition of rigid particles CaCO3 to PL40 enhances the modulus and the heat deflection temperature 4- Tc of PL40 with (10-40% CaCO3) increase while addition of AMPTES coupling agent reduce it. 5-Aminopropyltriethoxy silane (AMPTES) reduce the viscosity of PP/LLDPE blends