Polymer Exam 2 Pre-Challenge/Study Guide
Chapters 6 - 10
1) All machining and finishing of plastics present potential physical hazards.
2) Why do we test products to their maximum limits?
3) Several national and international agencies establish and publish testing specifications for industrial materials. Which of these is NOT one of those agencies?
4) The pendulum test measures_________.
5) The mechanical properties of a material describe how it responds to the application of force or _______?
6) All of the following are types of mechanical forces that can affect materials EXCEPT _____________ ?
7) Strain usually causes material to
8) Tensile strength is one of the most important indications of strength in a material. It is the ability of a material to withstand forces?
9) The value that shows how much force is needed to rupture or crush a material.
10) Shear strength is measure by ___________?
11) A plastic that resists the trasmission of vibration exhibits which property?
12) Scratch, mar, and abrasion resistance are closely related to?
13) The Rockwell, Wilson, Barcol, Brinell, and Shore are all well known testing tools used to test what?
14) The ratio of the mass of a given volume of material to the mass of an equal volume of water is called?
15) When creep occurs at room temperature, it is known as__________?
16) To obtain the most accurate measurements of a molded part, you should wait at least how many hours after molding?
17) Molded parts shrink when they __________ in a mold?
18) What is viscosity?
19) What happens to the molecular chains of thermoplastics when they are heated?
20) Handles of pots and pans are made of plastic that has a high __________?
21) What is specific heat?
22) What are ablative plastics used for?
23) What is glass transition temperature?
24) Why are many weathering test done in Florida?
25) Which of the following is NOT a hygroscopic plastic?
26) Which of the following is NOT among the most important optical properties?
27) What is a measurement of electrical voltage required to break down or arc through a plastics material?
28) What is oxidation?
29) Which of the following is NOT an effect of a plasticizer?
30) lubricants are used during the making of plastics because they ________?
31) What is a reason to include additives, reinforcements and fillers to plastics?
32) What type of light is destructive to plasitcs?
33) Dyes are ________ colorants?
34) Antistatic agents do what to plastics?
35) What is the name of material that has already been compounded to a desired color?
36) If heat causes electrons to release photons of light evergy, the radiation is referred to as?
37) Which pigments possess an after glow? That is, they continue to emit light for a limited time after the exciting force has been removed.
38) The two major types of foaming agents are?
39) What chemical agent is used to block the premature polymerization of resins?
40) A(n) ___________ is added to plastics to help them to cross link?
41) Chemical foaming agents release gases due to a chemical reaction.
42) These are additives that retard the decompositon of a ploymer caused by heat, light energy, or oxidation.
43) What material will show up as an irregular cloudy patch on the molded plastic surface?
44) Lubrication bloom is caused by _____________ applied to a mold.
45) What are used to lower the surface tension between compounds?
46) Plasticity refers to the ability of a material to ?
47) What is a polymer reinforcement?
48) Fibrous reinforcements are divided into these sub-classes: glass, carbonaceous, polymer, inorganic, metal, and __________ .
49) What is an important subclass of the fibrous group of reinforcements?
50) Fillers are what shape?
51) Which is NOT a basic plastic material?
52) What material is often used to make the lenses in eye glasses?
53) MFI stands for?
54) The polymerization process always needs two major chemical reactions which ones are required?
55) Additive polymerization is another name for?
56) The length of molecular chains affect the plastic's ___________ ?
57) In bulk polymerization, narrow __________ reactors guarantee a high ratio between surface area and volume.
58) This process utilizes water to surround the tiny droplets of monomer?
59) Small drops of monomer added to a large bath of solvent refers to
60) the most common by-products of stepwise polymerization are acetic acid, hydrogen chloride and ?
61) Materials polymerize by what type of reaction in reaction-injection molding?
62) What does the GP in GP-grades stand for?
63) What is the best source of information about a plastic?
64) Oversized taps and dyes should be used when theading plastics.
65) What causes drilled holes in plastic to become smaller than the diameter of the drill used.
66) A cut made by a saw is known as a _____?
67) For cutting plastic, circular saw blades should have plenty of set or be _____________?
68) What is the proper rake angle of a saw tooth used for cutting plastic?
69) Thermosetting plastics are ____________?
70) Which factor affects the cutting speed of plastic?
71) The distance, for each revolution, that the tool is fed into the work is called _______?
72) What grit number of sandpaper should be used for final finishing of plastics?
73) Climb-cutting is also referred to as?
74) A laser cutting machine may be used on plastics to cut out complex patterns.
75) Induced Fracture cutting methods are similar to cutting?
76) Which cutting process utilizes wires to cut plastic?
77) What type of abrasive is used on machines to prevent clogging or loading?
78) The thermal properties of thermoplastics make what difficult?
79) Which is NOT a buffing compound?
80) Which of the following is NOT a plastics molding process?
81) What is the name of the finishing method for plastics that places plastics in a drum with abbrasives?
82) All machined plastic parts should be ____________ before cementing.
83) Internal stresses may develop in plastic during which process?
84) What is the name of the process that removes internal stresses while slowly cooling the plastic material?
85) Which of the following is NOT an advantage of injection molding?
86) What are the two major components of injection-molding machines?
87) What part of an injection molder has the task of opening and closing the mold and ejecting the parts?
88) Which of the following is NOT an advantage of Compression Molding?
89) Electrical Interlock is used for?
90) Hydraulic interlock devices should prevent the mold from closing when the door is open.
91) Pellets may melt together in the bottom of an injection molder hopper to form a ________?
92) The maximum amount of material that a machine will inject per cycle is?
93) What is the maximum force that a machine can apply to a mold?
94) The time that is takes to open a mold, remove the molded part, and close the mold is called?
95) Fill time is the time it takes _________?
96) What is Coinjection molding?
97) What does RIM stand for?
98) _________ molding is placing a plastic material into a mold cavity and forming parts by applying heat and pressure?
99) The process of compressing a powdered plastic into a mold at temperatures just below its melting point for about one-half hour is called _______?
100) What is the disadvantage of transfer molding?
101) The term 'cellular plastics' refers to what type of plastics?
102) Which of the following type of plastics is made up of cells that are interconnected?
103) Which type of plastic is made up of individual bubbles or cells?
104) Which of the following is NOT an advantage of cellular plastics?
105) Which of the following is not a type of foam expansion process?
106) What is the name given to composite materials that are made up of multiple layers of reinforcement?
107) Which is the correct start up and shut down sequence for using the hot gas welder?
108) When rotational molding in the laboratory, how much pigment should be added to the powdered polyethylene to color the molded artifact?
109) What do you call the first coating of resin applied to a composite mold that creates the visible finished surface of the artifact.
110) What material are we using in the laboratory to construct our thermoforming molds?