ss_5 - 2. Consider two different solid poly(styrene) solids...

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Unformatted text preview: 2. Consider two different solid poly(styrene) solids at room temperature. One has an average degree of polymerization (DP) of 30. The other has an average DP of 1000. If identically shaped specimens of each polymer are loaded in tension, would you expect the maximum load that each could sustain to be the same or different? Briefly justify your answer. ”:_unopeowwcnfimwowawmiflhfli L“? :_ WOO} To \y’z NELE: TD germa— N awash m3 Ema \‘T'S ewhWR L?” %& Mmatwm;aJN£fl$ WLQLQ kkS bunk N®>T¥fiflfifii Gfi§'$&k E ?”SW““7 gunk Kw %AM&5M@« [_________._____l 5. Methane (CH4) has a lower boiling temperature than water (H20). Briefly explain why this is true in terms of the bonding between molecules in each of these two substances. .\.\ l \a - Ci“ ' O ‘ \ h H RL‘cmale'g-Txrfi‘xb \ mo EWM (KW: ' b\$x—WS 'M W ’0 ’X : ’25 63W 0"“ WU" “‘3 L g was 9&ch ‘0”‘C 7L = '53 CDWoW W W 0 C. V»; 459% {R M) CoubVLQvHJ—WY \AJ‘RTCJI WLULCULES W“ ® mm \‘5 k W Yards 3‘! gem-ma Mbme 25mg 5 wWS ,DW‘ eat". wab $9, WM WWW! magnum bub m3 . [—__—____'——_—_l 7. Suppose you are trying to select a material for use as the hood of a car. List the important properties required by this application and briefly indicate why a polymeric material would or would not be good for it. Low bausmy - Von/{vats M 195 vs {tr/5h W%\L\W '- vac/WI Ev‘nk Wovw‘hc Nu; . 455%,? M \JW)! W PAW“: . p0”? fifi'ttrWV “WE-u a”: Way-o4? Lia—ah a; \xxm smwb'w .. $542k w EMS W3“ a 29 per?“ sownmv mm “A mum-seas. \MDNX Eta Mm” ‘L y Wfix‘m— {YD B‘ch 7—» put gut-t- mtm ‘1 mezm‘wvfi 3 W W5 NOT" $052». uramab $€dheb8 5&2 “Ni- W——“----————., 8. From the following list, check all the valid reasons for using a polymer in place of an aluminum alloy. The polymer has: I better formability; _/ lower density; __ higher modulus; w higher melting temperature. Briefly justify your reasoning. @ §DMV5LCVZ ‘" mafia kkwimm f: k WU"! bat/110% Warm-L) We: Witithfit Vflocwaswe m: Momm \s W! \uw$\u¥c, Ppr% M WLL‘I W WwKW, (9 m We ix Hsz Weuws Pbecpme NE 0946wa (99 FCU’fihZ'l—fy \LJ N \5 m gmmfimg. (9‘9. Smoxfi Veil/i Mela? RowhS, {p 56mm} WWW/1g W HUI/M Lam Whoeug lb‘tfimbfi U, WW 5EZ0Q>R3D7 W53 Nae sfi%m_ Eb) Tf‘: 64oz We‘r- mmr VOW Maw Ti“ 4;: \Oo “700°C '——__—__—_———_l 10. The average molecular weight of a solid 1 gram sample of poly(ethylene) is 400,000 g/mole. Calculate the average degree of polymerization. Estimate the length of the average molecule in this sample. In the solid, with (roughly) what probability do you expect that the ends of this molecule will be this distance apart? Briefly justify your answer. \-\ \Jt MW .r W\+‘2x\7= \ \ , Cl C- \ \ \:t it “a W‘Eoskx \c" Wes-w NMWWM/ 0. \g M “=5 W???“ NR ‘ \‘3 N O-3 M“ LONG' \Vt‘isé x 07%» > L\’Z%é M I All h w) “to 4 Sign LEQPCW, |————-————______ 14. So-called ultrahigh molecular weight polyethylene (UHMWPE) is typically used in the cup portion of hip implants. (a) Suppose in one particular sample the average molecular weight is 4,000,000 g/mole. Calculate the average degree of polymerization. (b) Assuming the density of polyethylene to be 0.95 g/cm3, estimate the number of UHMWPE molecules in a 10g sample. (c) Would you expect the degree of polymerization to be the same for each of these molecules. Briefly justify your answer. W“: W 00 ” "i (\T- \VQ‘OIWO (9 LX‘OD'OJQ Wwéi \0 ‘25” (you-Mo?” hvtkluwx mu, u\- 7‘ ‘06 697% mug! 3 = \.<l Me‘ thacoteS \30. Wt ¥RESZML N613 eruuzx es \e W was;th swab \MW 3 %sc._ts~ese W Nx Nu waited?» when “ma (sane m Lamas w e mm. W \axsvwaxm 534% MW: BURNET- ésvmmgg VblictCfiO—sfi mm m We Mb Wmemw EM was s?" \bW—W mega. h straits“): Lit-Wrg I fl |____.__ 15. Is the glass transition temperature of an elastic band above or below room temperature? Briefly justify your answer. W @595 WWW Wag 99 H mm? QEM‘B \% Efikow Rant—x affixme kak‘fm Kai w Wewidzfim. ...
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ss_5 - 2. Consider two different solid poly(styrene) solids...

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