Ch. 13 Thick Barrier Linings

Question 1

What are the two major classes of rubber?

Answer 1

Natural and Synthetic

Question 2

What is vulcanization?

Answer 2

a psysicochemical change that results from cross linking the saturated hydrocarbon chain of natural rubber (polyisoprene) with sulfur, and applying heat.

Question 3

Three factors that affect the properties of the vulcanized product are:

Answer 3

Percentage of sulfur and accelerator used

Temperature of curing process

Time of cure

Question 4

List the carious methods used to cure (vulcanize) rubber.

Answer 4

Autoclave (vulcanizer) cure
Internal steam cure
Atmospheric steam cure
Hot-weather cure
Chemical cure

Question 5

The three categories of natural rubber are:

Answer 5

Soft
Semi-hard
Hard

Question 6

Describe a “tri-ply” lining

Answer 6

a layer of a hard or a semi-hard rubber between two layers of soft rubber

Question 7

Some various types of synthetic rubber are

Answer 7

Butyl rubber 
Neoprene rubber
Nitrile rubber
Chlorobutyl
Hypalon

Question 8

Describe the typical surface preparation requirements to install a rubber lining

Answer 8

NACE No.1/SSPC-SP5 white metal blast with a surface profile of 1.5-2.5 mils. Ensure surface is free of dust/debris before applying adhesive (primer)

Question 9

Some of the causes of rubber lining failure may be

Answer 9

Incorrect product selected for the intended service

Rubber used after expiration of shelf life

Using a rubber lining that was not properly stored. Keep rubber cool in stroage because, with heat, it can vulcanize onthe roll.

Incorrect application process used

Inadequate cure

Question 10

Three methods to apply polyethylene are

Answer 10

Melt the resin then extrude it onto the article to be coated

Heat the object to be coated to a temperature above the melting point of hte polyethylene then immerse the object in a fluidized bed of powder

FLame spray the polyethylene directly onto a metal surface. This method requires special equipment and operator expertise