Introduction of Polymer Study Guide

Question 1

what are 2 types of hydrocarbons that monomers can be classified as? which his more susceptible to polymerize and why?

Answer 1

saturated hydrocarbons and unsadurated hydrocarbons

unsaturized hydrocarbons, they can form new bonds because all there attachments are not taken up by hydrogen

Question 2

list and briefly describe the classification of a polymer

Answer 2

they are classified by chemical composition, molecular weight, and molecular structure

Question 3

schematically describe each of the copolymer chain structurers (block, graft, alternating, or random)

Answer 3

• random – A and B randomly vary in chain • alternating – A and B alternate in polymer chain • block – large blocks of A alternate with large blocks of B • graft – chains of B grafted on to A backbone

Question 4

what is a saturated carbon

Answer 4

all of its available bonds are attached to hydrogen. no room for additional bondage

Question 5

state and schematically describe the three steps in free radical/chain polymerization

Answer 5

initiation
propagation
termination

(see slides

Question 6

what are the three possible chain tacticity found in polymeric chains

Answer 6

Tacticity – stereoregularity of chain

isotactic – all R groups on same side of chain
syndiotactic – R groups alternate sides
atactic – R groups random

Question 7

what are ways to quanitify polymeric chain size?

Answer 7

number average weight (less accurate)

weight average weight

Question 8

what are different covalent chain configurations? List in order of increasing strength

Answer 8

linear, branched, cross-linked, network

Question 9

what is the difference between a saturated and unsaturated hydrocarbon

Answer 9

saturated hydrocarbon is connected to four other atoms and has no other availble bonds for addition bonding. unsaturated hydrocarbon has available bonds for bonding

Question 10

what is thermoset polymer? give example

Answer 10

• long chains with limited or no cross linkage, behave in plastic ductile maner, easily recyled,,,,, water bottle

Question 11

what is a thermoset polymer? give an example

Answer 11

highly cross linked. generally brittle, decompose when heated and are not recycled.
matgresses, adhesives, shoe soles, flooring

Question 12

what are elastomers and rubbers?

Answer 12

• large amounts of elastic deformation
• some light cross linking
• this cross linking allows material to return to original shape without plastic deformation

Question 13

what are different kinds of copolymers

Answer 13

random – A and B randomly vary in chain • alternating – A and B alternate in polymer chain • block – large blocks of A alternate with large blocks of B • graft – chains of B grafted on to A backbone

Question 14

what are some examples of polymer additives

Answer 14

fillers- wood flour, glass, silica gel
stabilizers- uv protectants, antioxidants
colorants-dyes or pigments

Question 15

name different processing methods of plastics

Answer 15

molding-compression or transfer

extrusion
blown film extrustion
blow modling

flour -roll calendar

fiber drawing

Question 16

what is polydisperisty index? PDI

Answer 16

ratio of Mw to Mn is this

Question 17

state the difference between cis and trans isomers in a polymeric chain

Answer 17

cis-bulky groups on same side of chain

trans-bulky groups on opposite side of chain

Question 18

describe polymer crystallinity. describe how polymer crystal forms

Answer 18

crystals must contain the polymer chains in some way
chain folded structure

it is more crystalline if the chains are more alline. rarely are they 100% crystalline (or alligned)

polymer crystals for through SPHERULITES- its a fast growth forms lamellar structures