What Is The Important Characteristics Of Plastics?
Answer :
It can be molded into finished product by application of heat and pressure.
What Are The Advantages Of Plastics Over Metals?
Answer :
Low weight
Corrosion resistance
Insulation properties
Electrical properties
Cheaper
Easy to handle
Surface properties
Reusable
Explain The Disadvantages Of Plastics?
Answer :
Low strength
Low heat resistance
Poor mechanical properties
Difficulty to repair
How To Classify The Plastics?
Answer :
Natural : milk of rubber tree, cellulose
Semi synthetic
Synthetic
Types Of Plastics Based On Chemical Behavior?
Answer :
Thermo plastics
Thermosetting plastics
Difference Between Thermo Set And Thermo Plastics?
Answer :
Thermoplastics:
Thermo set plastics:
Cannot be re softened and reused
Chemical changes during heating etc.
In powder form
Cross linked structure
Hard and brittle
Can be re softened and reused
No chemical changes during heating.
In granular form
Needle structure
Hard but not brittle
Give Example Of Thermoplastics?
Answer :
ABS, PP, CA, PMMA, PS, PC, POM etc.
Perspex Is The Trade Name Of ---- ?
Answer :
CA
Nylon Is The Trade Name Of ---- ?
Answer :
PA
Delrin Is The Trade Name Of ---- ?
Answer :
POM
Teflone Is The Trade Name Of ……….?
Answer :
PTFE
What Is Mfi?
Answer :
Flow capacity of different grades of thermoplastics are inversely proportional to molecular weight.
About Abs?
Answer :
Shrinkage 0.5%. It is heat resistant, provides good insulation and exhibit electrical properties. Examples are general purpose safety helmets, pipe fittings, television, radio etc.
About Ca ?
Answer :
Shrinkage 0.3-0.8%. Its main properties are transparency and surface texture. Examples are Tool handle, goggles, TV screens.
About Hdpe?
Answer :
Shrinkage 3-4%. Main features of HDFE are high density, rigidity, strength, hardness and chemical resistance. Examples are milk bottle crates, fish boxes etc.
About Ldpe?
Answer :
Shrinkage 0.8-1.5%. It is crystalline and not available in transparent form. Examples are shopping baskets, waste baskets etc.
About Pa?
Answer :
Shrinkage 0.7-1.5%. It is tough and high rigid. Examples are light duty gears, sprockets, bearings etc.
About Pc?
Answer :
Shrinkage 0.5-0.7%. It is known optical transparency, rigidity and toughness. Examples are goggles, lenses, safety helmets etc.
About Pp?
Answer :
Shrinkage 1-3%. It is flammable and degradable in sun light and stable. Examples are air cleaner, garden furniture etc.
About Ps?
Answer :
Shrinkage 0.2-0.8%. It is clear, brittle and it can be easily molded. Examples are toys, house hold appliances, electronic housings etc.
