1. Thermoforming is the same as blow moulding.
a) True
b) False
Discussion
Explanation: The given statemet is false. Thermoforming and blow moulding are totally different processes. Thermoforming is the process in which an article is heated stretched and cooled to give it a desirable shape. Whereas, in blow moulding, the thermoplastic is heated and put into the desired container and then shaped by blowing air through it.
2. The CPET containers, made by thermoforming are stable upto what temperature?
a) 230°C
b) 150°C
c) 300°C
d) 500°C
Discussion
Explanation: CPET (Crystallized Polyethylene terephthalate)containers, made by thermoforming are stable upto 230°C. The optimum amount of crystallinity is 28%–32%. CPET containers must be crystalline enough to be heat resistant but not so crystalline as to be too brittle for the application, for example, impact resistance at freezer temperatures.
3. The two dominant means of thermoforming sheet for food packaging containers are _____ & _____
a) Solid phase pressure forming, liquid phase pressure forming
b) Liquid phase process, vapour phase pressure forming
c) Melt phase process, liquid phase pressure forming
d) Melt phase process , solid phase pressure forming
Discussion
Explanation: The two dominant means of thermoforming sheet for food packaging containers are melt phase process and solid phase pressure forming. The melt phase process is most applicable to monolayer structures that have relatively high melt strength at thermoforming temperatures, for example, HIPS, PVC and PC. The SPPF process is primarily used to thermoform PP, a crystalline polymer that is difficult to thermoform uniformly in melt phase machines due to the sharp decrease in melt strength (viscosity) at its melting point.
4. _______ are defined as plastics whose apparent density is decreased.
a) Cellular plastics
b) Polyplastics
c) Thermoplastics
d) Artificial plastics
Discussion
Explanation: Cellular plastics are defined as plastics whose apparent density is decreased substantially by the presence of numerous cells dispersed throughout their mass. The terms foamed plastic, expanded plastic and plastic foam are also used for cellular plastics. They have desirable properties such as, high strength-to- weight ratio and good insulating and cushioning properties.
5. In general, temperatures for melt phase thermoformed Polypropylene is greater than SPPF Polypropylene.
a) True
b) False
Discussion
Explanation: The above statement is true. In general, temperatures for melt phase thermoformed Polypropylene is greater than SPPF(Solid phase pressure formed) Polypropylene. It is melt phase thermoformed at 154°C–157°C and SPPF at 141°C–146°C, where it is still virtually a solid with high viscosity, requiring the application of strong forces.
6. The fibrous raw material for production of paper is called _______
a) Pulp
b) Hemicellulose
c) Cellulose
d) Lignin
Discussion
Explanation: Pulp is the fibrous raw material for the production of paper, paperboard, corrugated board and similar manufactured products. It is obtained from plant fiber and is therefore a renewable resource.
7. Paper derives its name from _________
a) Papyres
b) Pyrus
c) Palpable
d) Papyrus
Discussion
Explanation: Paper derives its name from the reedy plant papyrus, which the ancient Egyptians used to produce the world’s first writing material by beating and pressing together thin layers of the plant stem.
8. Which of the following is not a constituent of the wood cell wall?
a) Cellulose
b) Pectin
c) Hemicellulose
d) Lignin
Discussion
Explanation: Pectin is not a constituent of the wood cell wall. It is a heteropolysaccharide present in primary cell walls of plants. It is responsible for the structural integrity of the cell. There are three main constituents of the wood cell wall – Cellulose, Hemicellulose and Lignin.
9. Paper greater than _______ g/m2 is called paperboard.
a) 200g/m2
b) 100g/m2
c) 500g/m2
d) 300g/m2
Discussion
Explanation: Paper greater than 200g/m2 (GSM) is called paperboard, as defined by ISO. GSM- Gram per square meter is used to express the amount of fiber. Paperboard is thicker than paper and has a higher weight per unit area.
10. _______ refers to the process wherein wood or other fibrous raw materials are reduced to a fibrous mass.
a) Pulping
b) Forming
c) Sheeting
d) Draping
Discussion
Explanation: Pulping refers to the process wherein wood or other fibrous raw materials are reduced to a fibrous mass. Pulping is done to separate the fibers without damaging them so that they can then be reformed into a paper sheet in the papermaking process.