Ijraset Journal For Research in Applied Science and Engineering Technology

Abstract

The objective of the present is to investigate hollow glass microspheres (HGMs) experimentally and carry out design analysis of hollow glass microsphere loaded PP/ABS composites. The tensile and notched Charpy impact test of HGM-filled acrylonitrile-butadiene-styrene copolymer (ABS) and Polypropylene (PP) composites will be studied with varying the concentrations of PP/ABS composite with HGM. Also further the design analysis will be studied by conducting the simulation under the same criteria and comparing the results at the end. This is done to introduce a light weight material without compromising specific strength of PP/ABS composite by adding HGM to the composite.

Introduction

I. INTRODUCTION

With the increase in industrial demands it is very essential to build materials that are strong but have less weight.Vivek et al. [13] investigated the effect of nano-sized alumina particles in ABS thermoplastic composites in which ABS was reinforced with nano-sized alumina particles via melt compounding.SEM micrographs revealed a higher dispersion rate, and ABS demonstrated a 10% increase in weight loss at a specific temperature. At 3vol% alumina content, the flexural modulus increases by about 23%.Budrun et al. [4] experimentally examined the mechanical and physical behaviors of the ABS reinforced with palm fiber.

Dunne  et  al.  [11]  pragmatically  carried  out  the  Mechanical  testing  of  natural  fibre composites using an acrylonitrile butadiene styrene matrix  (ABS).  The poroelastic natural fibre composites had tensile strengths ranging from 171 to 599 kPa. The airflow resistivity of 100 percent kenaf was found to be the highest. The 50% kenaf composite had the lowest airflow resistivity and tensile strength, but also the lowest density, which is a good thing. The densities of the poroelastic natural fibre composites still need to be optimized. S.M.D Mastan et al. [12] empirically determined that  in  the  presence  of  a  compatibilizer,  hybrid  PP/ABS  reinforced  fillers  were  successfully prepared using a twin-screw extruder followed by injection moulding. The addition of hybrid fillers increases the percent crystallinity of the PP phase in a PP/ABS blend, as does the thermal stability of the PP/ABS blend.

Kareem et al. [7] kept the figures in which the matrix is made of polypropylene, and the filler is made of waste tyre particles and the PP had a density of 960 kg/m3 and a flow index of 1.35 gm/min.The coefficient of thermal expansion for rubber particles polypropylene composite is 0.00022 mm/ mmC on average across the entire temperature range, which is 20% lower than the CTE of PP. As a result, the CTE of rubber particles polypropylene   composite   is   lower   than   that   of   PP   polymer,   resulting   in   rubber   particles polypropylene composite having better dimensional stability than PP polymer. Ganesh et al. [5] mixed ABS as a rubber phase copolymer and carbon black (CB) as a filler material.Tensile strength  and  Tensile  Modulus  Were  Increased   By  Adding  a  2.5  Wt%  Of  Cb  Filled  80/20(Wt/Wt) Pp/Abs Blends, And Impact Strength Was increased by adding 5 wt% of CB filled 80/20(wt/wt) PP/ABS blends.

Bruno  et  al.  [3]  mentioned  about  the  pellets  that  were  made  by  combining chopped carbon fibre in two lengths (3 mm and 6 mm) with ABS GP-35 at two different weight percentages (5 percent wt and 16.7 percent wt). At temperatures above 200°C, the ABS polymer displayed  signs  of  degradation  in  the  FTIR  spectra.Aiah  Mohamed  et  al.  [2]  investigated  the  mechanical,  melt-flow,  and  morphological actions of perlite reinforced ABS composites.Tensile strength of ABS/PER  composites  improved  with  2.5  percent  and  5  percent  PER  inclusions.Further  additions  resulted  in  a  decrease  in  tensile  strength  values  which  was further examined by SEM on identifying presence of weak interfacial interactions.

The aims of the study are:

1. To fabricate hollow glass microsphere loaded PP/ABS composites with different weight% of HGM.
2. Carry out Experimental Investigation to test the strength of the various samples.

II. EXPERIMENTAL WORK

A. Materials Required

Polypropylene  is  chosen  as  matrix  due  to  its  huge  usage  in  market  and  easiness  in  making  a composite. The benefits of polypropylene (PP) include high heat alteration in temperature, better processibility, and low cost. Its only drawback is that it has lower impact properties. It is combined with Acrylobutadiene Styrene for this purpose (ABS). Among the various polymers, PP is a critical plastic commodity that is widely used to manufacture products by a variety of industries..They are also used in buildings and switch boards for their insulation property. Hollow glass microsphere is chosen   as   the   particle   reinforcement   for   its   low   density   and   high   compressive   strength. Polypropylene is selected due to its immense applications in commercial market and    it can be easily moulded into a composite. Polypropylene (Injection Grade-H110MA) was procured from Guntur after thorough search in Chennai and Bangalore. The composite is to be manufactured with PP/ABS  as  matrix  and  hollow  glass  microsphere  as  the  particle  reinforcement.  The  weight percentage of hollow glass microsphere in the PP/ABS matrix is varied to enhance both mechanical and  thermal  properties  of  the  matrix.  Samples  with  varying  weight  percentage  of  hollow  glass microspheres  are  extruded  and  further  moulded  for  tension  and  impact  tests  using  injection moulding machine. Mould for compression test sample is not available.

B. Mixing of Particles with Matrix

Polypropylene/Acrylobutadiene  Styrene  matrix  is  mixed  with  hollow  glass  microsphere.  Five samples are prepared having the following weight percentage of HGM - 0, 5, 10, 15 and 20. The remaining  weight  percentage in  the  sample  consists  of  polypropylene.  Each  sample  has  a  total weight of 100 grams. Weight of the sample constituents is carefully measured by the weight balance and is stored in beakers for further processing. Beakers are covered with aluminium foil. The five beakers are dried in an oven in vacuum environment for one hour to remove any moisture present in the sample at a temperature of 40 degree Celsius.

C. Preparation of Composite

Four plastic bags containing the matrix of weight 150 grams is used in the twin screw extruder to clean any sample left over from the previous operation. Temperature in the three chambers of the twin screw extruder are 120, 220, 250 degree Celsius to ensure that the sample can be extruded without degradation. The samples are fed into the twin screw extruder in conical flask with help of spatula. While the mixture travels through the heating chambers of extruder, mixture gets heated and gets melted. This melted mixture is received at the other end of extruder through a small circular cross section hole in the form of continuous wire. Feeding of mixture in the flask should be slow enough especially with samples with higher composition of hollow glass microspheres as it being in the nature of powder tends to get carried away in the air. Extruded material obtained from the extruder is pulled at the correct speed to ensure the correct thickness. Too high speed results in a thin cylindrical mixture whereas during a slow speed the sample tends to wound near the extrusion hole.  The  extruded  material  coming  out  initially  from  the  hole  is  ignored  as  it  may  contain constituents of the previous sample which was extruded. Collected extruded material is further chopped into small pieces for ease of storing, carrying and injection purpose.

D. Injection Moulding

Tensile and Impact samples are prepared by injection moulding process.The chopped pieces are fed into the injection moulding machine through a conical flask to make two UTM moulds and two Impact moulds for each sample. The temperature is set at 235 degree Celsius in the machine for the sample to be forced into the mould. The mould is kept in the injection moulding machine for three minutes so it is at a higher temperature which reduced thermal cracking and allows more uniform heating.After injection, the mould is opened and the Tension / Impact mould is extracted by a hammer and nail. Impact sample was also prepared by the same procedure with the mould being changed to get the desired shape for the impact sample.

E. Tensile Test

The tensile strength of the PP/ABS and hollow glass microspheres composite specimen is tested using a Universal Tensile Testing machine. The test specimen was prepared in accordance with ASTM standards D3037/3039. Injection moulding was used to create two dumbbell-shaped samples of each set of PP/ABS composites with different compositions of hollow glass microspheres. The width and thickness of dumbbell bridge samples were measured using a digital Vernier Calliper.The test was performed at a pulling rate of 3mm/min. After the sample was measured, the software recorded  the  tensile  strength,  modulus, and  elongation  at  break.  SEM  was  used  to  examine  the tensile fracture surface in order to determine the nature of the fracture.

F. Impact Test

The impact strength of the PP/ABS and hollow glass microspheres composite specimen was tested using an impact testing machine. The apparatus is made up of a known mass and length pendulum that is dropped from a known height to strike a notched specimen of material. The amount of energy transferred to the material can be calculated by comparing the height of the hammer before and after the fracture (energy absorbed by the fracture event).

G. Scanning Electron Microscopy(SEM)

SEM is an important characterization tool to directly imaging micro particles in order to obtain quantitative measures of particle, grain size, and morphology.The fractured surfaces of the HGM reinforced with PP/ABS composite were SEM-ed to investigate the   HGM-PP/ABS   interaction   and   the   microstructural   changes   that   occur   when   HGM   is incorporated  into the  PP/ABS matrix.

III. RESULTS AND DISCUSSIONS

A. Density

TABLE I
Experimental Density of Each Sample

Fig. 1 Density of Each Sample

Results from Table I and Fig. 1 show the decrease in density as the percentage of HGM increases in the composite of PP/ABS with minimum of 0.518 at 20% . Structure of hollow glass microspheres is hollow by nature. Thus, sample having higher weight percentage of hollow glass microspheres will have lower density than those with lower percentage.

A. Tensile Strength

TABLE III
Tensile Strength of Each Sample

Results from Table 3.2 show that the composite has a maximum value of Ultimate Tensile strength of 34 when hollow glass microsphere are absent. The composite has a maximum value of Young’s Modulus  of  0.793155  when  weight  percentage  of  hollow  glass  microspheres  is  20%  in  the composite.

Fig. 2 Tensile strength of PP/ABS based composites with the variation of HGM

C. Ansys Simulation

Fig. 3 (a)Ansys Simulation for pure PP/ABS Composite and (b)Results for Ansys simulation (PP/ABS).

Fig. 4 (a)Ansys Simulation for 5% HGM in PP/ABS Composite and (b)Results for Ansys simulation (PP/ABS) with 5% HGM.

Fig. 6 (a)Ansys Simulation for 15% HGM in PP/ABS Composite and (b)Results for Ansys simulation (PP/ABS) with 15% HGM.

Fig. 7 (a)Ansys Simulation for 20% HGM in PP/ABS Composite and (b)Results for Ansys simulation (PP/ABS) with 20% HGM.

TABLE IIIII
Results of Ansys Simulation Compiled with Experimental Results

The results of experimentation and simulation for tensile stress match each other with minor error as shown in Table III.

D. Impact Energy

TABLE IVV
Results of Ansys Simulation Compiled with Experimental Results

Fig. 8 Impact energy of PP/ABS based composites with the variation of HGM.

Results from Table IV and Fig. 8, show there is an increase in Impact Energy among the samples up to a concentration of 15% of HGM by  weight in  the composite, but decreases on further increase in concentration of HGM.

Table V

Effect on Tensile and Impact Strength of PP/ABS Composite

It is advisable to use polymer composite with either 85 or 90 weight percentage of PP/ABS (Table V) if high impact strength is required as they exhibit the highest impact strength and absorb more energy per unit area compared to others.

E. Scanning Electron Microscopy

Fig. 9 HGM's SEM micrograph is shown. The morphological characteristics of these HGMs are spheres with smooth surfaces and average diameters ranging from 10 to 50 m.The fractured surfaces of the HGM reinforced with PP/ABS composite were SEM-ed to investigate the   HGM-PP/ABS   interaction   and   the   microstructural   changes   that   occur   when   HGM   is incorporated  into the  PP/ABS matrix. The fractured surface of the  pure  PP/ABS specimen was micrographed (Fig. 10), The fracture has been observed to be brittle in nature.The fractured surface is smooth with very little roughness.The SEM micrographs of the HGM/PP/ABS composite show that the HGM has good contact with the  PP/ABS  matrix  (Fig. 11 and 12).  The  morphology  of  the  fractured  surface  changes dramatically after the HGM content is introduced. In the presence of HGM, the smoothness of the fractured surface decreases, indicating a brittle to ductile transformation in the composite matrix.

IV. ACKNOWLEDGMENT

The Author would like to take this opportunity to ackmowledge the financial support and opportunities provided bz Vellore Institute of Technology (Vellore),India for carrying out this research work.

Conclusion

A. In this work, the effect of addition of hollow glass microspheres to PP/ABS matrix was studied .Because of the hollow structure of hollow glass microspheres, samples with a higher weight percentage of hollow glass microspheres have a lower density than those with a lower weight percentage. B. Tensile stress at break decreases as the weight percentage of hollow glass microspheres increases in PP/ABS matrix. C. The composite has a maximum value of Young’s Modulus when weight percentage of hollow glass microspheres is 20% in the composite. D. Value of true strain at maximum load is higher in sample having 10 percentage of hollow glass microspheres in the PP/ABS matrix. E. SEM micrographs of the composite show that the hollow glass microspheres make good contact with the PP/ABS matrix. With the addition of hollow glass microsphere content, there is a significant and noticeable difference in the morphology of the fractured surface\'s surface. F. The presence of hollow glass microspheres reduces the smoothness of the fractured surface, implying a brittle to ductile transformation in the composite material.

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Copyright

Copyright © 2022 Shreyas Biswas. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.