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University of TripoliFaculty of Engineering

Metallurgical Engineering and MaterialsScience

Graduate Studies

Home work no. 1

Properties &structure of polymerMME 680

(spring- 2013)

A- Name and Structure of Polymer


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1-Polydimethylsiloxane(Tg=-123)

2-Polyethylene(Tg=-120)

3-Poly-(cis-1,4-butadiene) (Tg=-90)


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4-Poly-(cis-1,4- methyl butadiene ) (Tg= -73)

5-Natural r ubber(Tg= -72)
https://en.wikipedia.org/wiki/Natural_rubberhttps://en.wikipedia.org/wiki/Natural_rubber


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6 -Butyl rubber( Polyisobutylene)(Tg= -65)

It has a structure similar to polyetyhylene, except that each second carbon atom

in the polymer chain is bonded to two methyl (CH3) groups. It is derived from

the monomer isobutylene thus:-

Figure:- Structure of isobutylene and polyisobutylene or butyl rubber.

7-polychloroprene (Tg= -50)
http://www.google.com.ly/search?q=structure+of+butyl+rubber&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=hhClUYvzHcPZPMTagYAL&ved=0CEoQsAQhttp://www.google.com.ly/search?q=structure+of+butyl+rubber&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=hhClUYvzHcPZPMTagYAL&ved=0CEoQsAQhttp://www.google.com.ly/search?q=structure+of+butyl+rubber&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=hhClUYvzHcPZPMTagYAL&ved=0CEoQsAQ


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8- Poly(vinylidene fluoride)(Tg= - 40)


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9- Poly-(cis-1,4- propylene) (Tg= - 15)

10-poly(methyl acrylate) (Tg= 10)

11- poly(vinyl acetate) (Tg= 29)


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12- poly(methyl pentene) (Tg= 30)

13-Ethylcellulose(Tg=43)
http://www.dow.com/dowwolff/en/industrial_solutions/polymers/ethylcellulose/http://www.dow.com/dowwolff/en/industrial_solutions/polymers/ethylcellulose/


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14-Nylon-6(Tg= 50)

15-cell ulose ni trate(Tg= 53)

16-Polyethylene terephthalate(Tg= 69)
http://www.google.com.ly/search?q=structure+of+cellulose+nitrate&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=1c2oUa3XNMKYtAaB3IDABg&ved=0CDAQsAQhttp://www.google.com.ly/search?q=structure+of+cellulose+nitrate&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=1c2oUa3XNMKYtAaB3IDABg&ved=0CDAQsAQhttp://www.google.com.ly/search?q=structure+of+cellulose+nitrate&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=1c2oUa3XNMKYtAaB3IDABg&ved=0CDAQsAQhttp://www.google.com.ly/search?q=structure+of+cellulose+nitrate&biw=1366&bih=631&tbm=isch&tbo=u&source=univ&sa=X&ei=1c2oUa3XNMKYtAaB3IDABg&ved=0CDAQsAQ


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17-Cellulose diacetate(Tg= 80)

18-Poly(vinyl alcohol)(Tg= 85)


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19-polyphenylenesulfide(PPS)(Tg= 85)

20-Poly(vinyl chlor ide)(Tg= 87)

21-Polystyrene(Tg= 100)


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22-poly(methyl methacrylate) (Tg= 110)


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23-Polyacrylonitrile(Tg= 120)

24-poly(tetrafl uoroethylene) (Tg= 126)


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25-polyetheretherketone(peek) (Tg= 143)

26-Polycarbonate(Tg= 150)

27-Polyvinyltrimethylsilane(Tg= 170)

28-polysulfone(Tg=190)
http://www.google.com.ly/search?q=structure+of+polyether+sulfone&biw=1366&bih=631&noj=1&tbm=isch&tbo=u&source=univ&sa=X&ei=9z2lUebnOYuO7AbthICwCw&ved=0CEwQsAQhttp://www.google.com.ly/search?q=structure+of+polyether+sulfone&biw=1366&bih=631&noj=1&tbm=isch&tbo=u&source=univ&sa=X&ei=9z2lUebnOYuO7AbthICwCw&ved=0CEwQsAQhttp://www.google.com.ly/search?q=structure+of+polyether+sulfone&biw=1366&bih=631&noj=1&tbm=isch&tbo=u&source=univ&sa=X&ei=9z2lUebnOYuO7AbthICwCw&ved=0CEwQsAQhttp://www.google.com.ly/search?q=structure+of+polyether+sulfone&biw=1366&bih=631&noj=1&tbm=isch&tbo=u&source=univ&sa=X&ei=9z2lUebnOYuO7AbthICwCw&ved=0CEwQsAQ


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29-Polytrimethylsilyipropyne(Tg= 200)

30-polyetherimide(Tg=210)

31-Poly-(2,6dimethylphenylene oxide" ppo" )(Tg=210)


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PPO is made of phenylene rings linked together by ether linkages in the 1,4

or para-positions, with a methyl group attached to carbon atoms in the 2

and 6 positions.

32-Polyethersulf one (PES)(Tg=230)

33-Polyimide(Kapton)(Tg= 300)


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34-Polyoxadiazole(POD) (Tg= 450)

B- Comparative between TG for Polymers

Introduction


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Before comparative between TG for a polymers most be know why some

polymers have high Tg's, and some have low Tg's. The very simple answer is

this :How easily the chains move . A polymer chain that can move around fairly

easily will have a very low Tg, while one that doesn't move so well will have a

high one. This makes sense. The more easily a polymer can move, the less heat

it takes for the chains to commence wiggling and break out of the rigid glassy

state and into the soft rubbery state There are several things that affect the

mobility of a polymer chain included:-

1-Backbone Flexibili ty(The more flexible the backbone chain is, the better

the polymer wil l move, and the lower its Tg wi l l be).

In many polymer the main chain consist entire ofc-c- bond which makethe chain flexible wile when the main chain is completely unsaturated

(ie. Constructed of- c=c bonds ) no rotation is possible and very rigid

chain obtained and in case of chain containing both saturated and

unsaturated bond

c-c-c=c-c-c- the rotation around the single bond is

still possible and the chain is flexible but less than single bond ; so that

when a polymer has a backbone with a single bond has lower Tg than

once a polymer has double bond and when another polymer have a

backbone with mixed bond Tg for this polymer is lowest than both

polymers .

Introduction of hetrocyclic and aromatic group in backbone of chainlead Tg.

Other element such as (nitrogen oxygen ) are linked with Carbon inbackbone chain the presence its increase the flexibility(ie ,reduced Tg )

but of then ormtic or heterocylic group are also present in backbone tend

to dominate the structure giving the chain rigid character .
http://pslc.ws/macrog/tg.htm#flexhttp://pslc.ws/macrog/tg.htm#flexhttp://pslc.ws/macrog/tg.htm#flex


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For polymer s does not contain carbon atom in the back bone chains(inorganic polymers) sometimes are flexible such as silicon rubber that

are containing silicon rather than carbon -si-o and another are rigid

such as poly phosphazene -p=N-

2- Side group such asPendant Groups " F ish Hooks and Boat Anchors" And

Pendant " Elbow Room". (Bulky side groups also increase Tg because of the

reduction of rotational freedom around the main chain )

Pendant Groups Part I : F ish Hooks and Boat AnchorsPendant groups have a big effect on chain mobility. Even a small pendant group

can act as a fish hook that will catch on any nearby molecule when the polymer

chain tries to move like corkscrew. Pendant groups also catch on each other

when chains try to slither past each other. One of the best pendant groups for

getting a high Tg is the big bulky adamantyl group. An adamantyl group is

derived from a compound called adamantane.

A big group like this does more than just act like a hook that catches on nearby

molecules and keeps the polymer from moving. It's a downright boat anchor.

Not only does it get caught on nearby polymer chains, its sheer mass is such a

load for its polymer chain to move that it makes the polymer chain move much

more slowly. To see how much this affects the Tg, just take a look at
http://pslc.ws/macrog/tg.htm#onehttp://pslc.ws/macrog/tg.htm#twohttp://pslc.ws/macrog/adam.htmhttp://pslc.ws/macrog/tg.htm#twohttp://pslc.ws/macrog/tg.htm#one


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two poly(ether ketones), one with an adamantane pendant group and one

without.

The Tg of the polymer on the top is already decent at 119 oC, but the adamantyl

group raises even higher, to 225 oC.

Pendant Groups Part I I : E lbow RoomBut big bulky pendant groups can lower the Tg, too. You see, the big pendant

groups limit how closely the polymer chains can pack together. The further they

are from each other, the more easily they can move around. This lowers the Tg,

in the same way a plasticizerdoes. The fancy way to say that there is more

room between the polymer chains is to say there is more free volume in the

polymer. The more free volume, the lower the Tg generally. We can see this

with a series ofmethacrylatepolymers:
http://pslc.ws/macrog/pek.htmhttp://pslc.ws/macrog/tg.htm#plasticizerhttp://pslc.ws/macrog/acrylate.htmhttp://pslc.ws/macrog/acrylate.htmhttp://pslc.ws/macrog/tg.htm#plasticizerhttp://pslc.ws/macrog/pek.htm


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You can see a big drop each time we make that pendant alkyl chain one carbonlonger. We start out at 120 oC forpoly(methyl methacrylate), but by the time we

get to poly(butyl methacrylate) the Tg has dropped to only 20oC, pretty close to

room temperature.
http://pslc.ws/macrog/pmma.htmhttp://pslc.ws/macrog/pmma.htm


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Comparative

Polyvinyltrimethylsilane Polytrimethylpropen

(a) Tg= -123 (b)Tg = 170 (c) Tg= 200

From the above structure of polymers we are clear to see the Tg for

polytrimethylpropen is higher than polyvinyltrimethylsilane due to the effect of

double bond in back bone and where the double bond decreased the flexibilityof polymer as so as decreases Tg and make hard rigid polymer but a single

bond in polyvinytrimethylsilane made a polymer less hardness and rigidity (i.e.

some flexibility occur) and when compare this polymer with

polydimethlsiloxane ,it has lowest Tg duo to the replaced the carbon by( si-o)

in main chain thats made flexible polymer and more chain movement.

polyethylene Tg= -120 Polystyrene(Tg= 100)


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Butyl rubberTg = -65

When the structure is simple and consisting of hydrogen bond around carbon in

back bone made some crystallinety and Tg is low then when the methyl

group bonded with Carbone such as butyl rubber and polyethylene the Tg

increases from -120 in polyethylene to -65 in nature rubber by present of said

group but whene replaced a hydrogen by vinyl group the Tg is change from

negative charge to positive charge (ie. Is a highest tg than those ) because the

ring of benzene made rigid hard polymer .

poly (cis ,1,4butadiene) Tg = -90 poly (cis ,1,4methyl butadiene) Tg = -73

Natural rubberTg = -72 Tg = -50

In above the all structure of polymer has a same back bone c=c double bond

structure but have different Tg due to different crystallinety or aside group

when compare the butadiene with methyl butadiene we see the methyl group

prevent the movement of chain so that increases Tg but the natural rubber less


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Tg due to hydrogen bond but when replaced the hydrogen bond by Cl bonded.

with carbon the CL reduced the flexibility chain as soon as increases Tg .

Polyvinylidene fluoride Tg = -40 Tg = 10

Polyvinyl acetate Tg = 29 Methyl pentene Tg = 30

Polyvinyl chloride Tg = 87 Polyvinyl alcohol Tg = 85

polyacrylonitrile Tg = 120


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the structure above all have the same back bone single (c-c )boned except

polyacrylonitrile where have a single bond with branched has three bonded of

carbon and N molecule these branched made hard rigid polymer and increase

the tg of chain into from negative signal to highest positive degree from -40

into 120 and we can so the effect of molecule that are bonded with c-c is

different see fluoride when bonded with c-c back bone is made flexible

polymer and decrease tg but when replaced by cl the cl increase the rigidity of

polymer and increase tg for polymer and OH molecule has about same effect

and when backbone of chain is bonded with group such as acetatemethyl cry

late-methyl the distribution of group and oxygen joint with carbon effect of

flexibility when the oxygen are joint in one side such as methyl acrylate is

increased the flexibility of chain which reduce the tg of chain and when is

capture between to carbon bond such as acetate increase tg by miner value but

when replace oxygen by the methyl group the tg still is higher than those

structure such as methyl pentene.

Polyphenylene sulfide Tg = 85

poly(2-6dimethylphenylene )Tg = 210 polyetheretherketone Tg = 134

We see from above Bulky backbone chain groups also increase Tg because of

the reduction of rotational freedom main chain such as cycle benzene and the

said group such ether increase Tg from above structure the in thePolyphenylene sulfide reduced tg and short length chain compared with ether


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and etherketone . and whene compare poly(2-6dimethylphenylene )with

polyetheretherketone the Tg for poly(2-6dimethylphenylene ) is above the

polyetheretherketone by 24 duo to the oxygen where made some flexibility .

Ethyl Cellulose Tg = 43 Cellulose nitrate Tg = 53 Cellulose diacetate Tg = 80

The bulky group present in cellulose increased Tg for chain see diacetategroup in Cellulose diacetate where increased the comparability of structure and

prevent the movement of chain but when replaced by small group such as

nitrate the Tg is decreased but it is still greater than Ethyl because the present of

nitrogen in side grope decreased the flexibility of movement of side group

about chain as so as the Tg of cellulose is increased from left to right (ie Tg of

Ethyl CelluloseCellulose nitrateCcellulose diacetate).

Tg = 190 Tg = 230


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Polysulfone backbone is just plain stiff but has some flexibility but when put

the ether group in chain backbone the polymer's it will be more rigid and stiff

as so as the Tg is high .

Tg = 50 polyoxadiazole Tg = 450

kapton Tg = 300

the position of nitrogen and oxygen molecule in chain it is effect in the Tg for a

polymer because the bond between these molecules and carbon-carbon effect of

flexibility of polymer thats we can be seen from above polymer where the

nylon 6 has six carbon same polyoxadiazole but the Tg for nylon 6 is less duo

to the rings of carbon distribution and the number of N and bonded it with

carbon and oxygen the same effect for kapton . but the kapton is less Tg

compared with polyoxadiazole duo to present oxygen that are distributed by

away increased the flexibility of chain and reduced Tg buy some value but still

higher duo to a complex ability of structure .

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