ABS vs SAN

Bismillahirrahmanirrahim.

In Material Engineering course, students are required to execute 3 projects which involve choosing a proper material based on criteria provided. Luckily for my team, we chose to make a research on Car Battery a.k.a accumulator for our first task. Division of labor among team members seem to be blended well, and my case  study is choosing the best material for the casing of the accumulator.

ABS and SAN. What are they? basically, ABS stands for :

Acrylonitrile Butadiene Styrene

whereas, SAN stands for :

Styrene Acrilonitrile SAN

both materials are derivative of styrene and of course both of them are polymers.

Well, the significance difference between these materials is ABS comes later after SAN. Which means, SAN is the predecessor of ABS.

We are normally exposed to these materials in our daily life since a lot of our daily applications and utensils are made from these polymers such as :

1. the outer casings of thermally insulated jugs, for tableware, cutlery, coffee filters, jars and beakers as well as storage containers for all kinds of foods. An additional application is in multi-trip tableware for the catering sector.

2. The pleasing appearance especially when coloured and the ease of printing on SAN has allowed a number of applications in the bathroom (toothbrushes and bathroom fittings) and cosmetic packaging,

3. in the office and in industry for diverse applications, all types of outer covers, e.g. printers, calculators, instruments and lamps.  Other applications include scales, battery housings, winding cores, writing and drawing equipment and cylindrical impellers for air-conditioners.

And of course, mainly the defect of car battery based on physical effects such that :

1. Thermal vibration of car battery that create crack and dislocation

2. Leakage of electrolyte due to improper battery cap

3. Low melting point of car battery, cause deformation of the shape, etc..

Well, these repercussions mainly arise due to low Young Modulus, Ultimate Tensile Strength, Low Material fatigue, low critical crack coefficient and many more. Based on the knowledge of Material Science.

ABS

PHYSICAL PROPERTIES Tensile Strength 40-50 Mpa Notched Impact Strength 10 - 20 Kj/m² Thermal Coefficient of expansion 70 - 90 x 10-6 Max Cont Use Temp 80 – 95 oC Density 1.0 – 1.05 g/cm3

RESISTANCE TO CHEMICALS Dilute Acid **** Dilute Alkalis **** Oils and Greases **** Aliphatic Hydrocarbons ** Aromatic Hydrocarbons * Halogenated Hydrocarbons * Alcohols * (variable)

KEY * poor ** moderate *** good **** very good SAN PHYSICAL PROPERTIES Tensile Strength 3.40 – 3.90 N/mm² Notched Impact Strength 250 Kj/m² Thermal Coefficient of expansion 70 x 10-6 Max Cont Use Temp 55 oC Density 1.08 g/cm3 RESISTANCE TO CHEMICALS Dilute Acid **** Dilute Alkalis **** Oils and Greases **** Aliphatic Hydrocarbons ** Aromatic Hydrocarbons * Halogenated Hydrocarbons * Alcohols ** variable KEY * poor ** moderate *** good **** very good

As ABS comes later than SAN, definitely improvement had been done towards this material. To my suprise, based on my research, there are loads type of ABS. One which I will highly recommend is ABS with 30% carbon fibre.

This material has high resistivity towards chemical reaction, thermal vibrations, hight Yield Strength, Tough, yet light. Which certainly the perfect match to build an ideal car battery.

In terms of cost, obviously it’s going to fly off since carbon fibre is qute expensive. However, if we think for the long run, this material will increase the life expectancy of the car battery up to 48 months in which current car battery which is made from SAN can only lasts for 24 months! it’s a future investment though.

Well, I’ve already done my part in this project. This Friday, we are going to have a meeting to refine and synchronize our ideas. There are 3 parts of research, one is the casing, one is the terminal, and one is the power line and we have to come up with the best raw material to make each of them.

I really enjoy this course as it provides me the opportunity to think like an engineer do. Critical and creative thinking. I am looking forward for much more hands on activities. Well, it really shows that the enjoyment of learning comes after we appreciate the knowledge from God. Obviously, we might encounter stress as we move on learning..but, handling stress is a part of knowledge..and in every bitterness, there is sweetness..I hope this post will encourage readers for not to take for granted any knowledge that you learned as knowledge makes a perfect indication between the bright and the fool…

” And if all the trees on earth were pens and the oceans were ink, with seven oceans behind it to add to its(supply) , yet would not Words of God be exhausted (in the writing): for God is Exalted in power, full of wisdom..” Chapter Luqman, verse 28

SUBHANALLAH!~

Wallahua’lam.

refference : http://www.bpf.co.uk/bpfindustry/plastics_materials_Styrene_Acrylonitrile_SAN.cfm