1. In Plasma Enhanced Chemical Vapor Deposition, deposition occurs at a _______ temperature.
a) Higher
b) Constant
c) Increasing
d) Lower
Discussion
Explanation: In Plasma Enhanced Chemical Vapor Deposition, deposition occurs at a low temperature. The use of plasma helps to deposit thin films from a gaseous state to a solid state on the substrate; hence it enhances chemical reaction rates. The plasma is created by alternating or direct current discharge between two electrodes. The space between electrodes is filled with reacting gases which contains reactive ions and radicals.
2. Which film is used for improving barrier properties of PET bottles?
a) PVC
b) PED
c) DLC
d) GLC
Discussion
Explanation: DLC (Diamond like Carbon) film is used for improving barrier properties of PET bottles. There is deposition of a very thin DLC film on the inner surface of PET bottle by PECVD mechanism. DLC film provides gas barrier properties, flavour barrier, UV barrier, chemical inertness, recyclability, etc.
3. Which of the following CVD technique is a flame based technique?
a) CCVD
b) PECVD
c) LPCVD
d) ALCVD
Discussion
Explanation: CCVD (Combustion Chemical Vapor Deposition) is a flame based technique. In this, the metal-bearing chemicals are first dissolved in a solution that typically is a combustible fuel. The solution is then atomized to form microscopic droplets that are carried by an O2 stream to the flame where they are combusted. The heat from the flame provides the energy required to vaporize the droplets and for the precursors to react and deposit on the substrate.
4. The term BOPP in packaging stands for _____
a) Biaxially Oriented Polypropylene
b) Biaxially Oriented Propylene Alcohol
c) Biaxially Oriented polyphenol
d) Biaxially Operated Packaging Printing
Discussion
Explanation: The term BOPP in packaging stands for Biaxially Oriented Polypropylene. It is generally used for packaging labels. BOPP is produced by stretching the polypropylene film in both directions. It results in higher strength and higher resistance to stress cracking and puncture.
5. Which of the following is used for shrink bundle?
a) BOPP
b) PVC
c) LLDPE
d) Cast PP
Discussion
Explanation: LLDPE-Linear Low Density Polyethylene is used for shrink bundling. LLDPE is a copolymer made up of ethylene and another longer olefin, whereas LDPE is a homopolymer made only of ethylene monomers. LLDPE has a greater tensile strength or resistance to harsh environment.
6. Oriented films have better sealability.
a) True
b) False
Discussion
Explanation: The above statement is false. Oriented film cannot be easily heat sealed because it shrinks and puckers at temperatures below the sealing temperature.
7. LDPE is generally irradiated before moulding into film.
a) True
b) False
Discussion
Explanation: The given statement is true. LDPE is generally irradiated before moulding into film, because radiation cross-links the molecules and the film can be stretched without becoming fluid at the melting point of a non-irradiated film, resulting in greatly improved tensile strength and shrink tension compared to non-irradiated LDPE.
8. __________ is the process which reduces the residual strain after the extrusion process.
a) Lacquering
b) Canning
c) Electroplating
d) Annealing
Discussion
Explanation: Annealing is the process which reduces the residual strain after the extrusion process. Films can be annealed by the application of heat to partially relax the forces while maintaining the film in a highly stretched condition. It is then cooled to room temperature and the restraint on the film released.
9. The film after annealing is called ________
a) Strict film
b) Film set
c) Heat set
d) Heat film
Discussion
Explanation: The film after annealing is called heat set. Heat set does not shrink even if heated below the annealing temperature. Heat set has more desirable properties. Annealing results in some reduction in dimension in the stretched direction or directions.
10. Which of the following methods are used for orientation of plastic films?
a) Tenter frame and bubble frame
b) Tenter frame and Double bubble
c) Tenter bubble and Double bubble
d) Tenter bubble and Double Frame
Discussion
Explanation: Tenter frame and Double bubble are the two methods are used for orientation of plastic films. It generally includes heating of the film and stretching it in uniaxial or biaxial direction on a tenter or double frame. The orientation decides the use of the film.