Thermal decomposition products of polypropylene

(1)

Publisher’s version / Version de l'éditeur:

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à [email protected].

Questions? Contact the NRC Publications Archive team at

[email protected]. If you wish to email the authors directly, please see the first page of the publication for their contact information.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

Research Paper (National Research Council of Canada. Division of Building

Research); no. DBR-RP-404, 1969-06-01

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. https://nrc-publications.canada.ca/eng/copyright

NRC Publications Archive Record / Notice des Archives des publications du CNRC :

https://nrc-publications.canada.ca/eng/view/object/?id=5a927633-46c0-42e8-96e8-1cd7f612dd47 https://publications-cnrc.canada.ca/fra/voir/objet/?id=5a927633-46c0-42e8-96e8-1cd7f612dd47

NRC Publications Archive

Archives des publications du CNRC

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.

For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

https://doi.org/10.4224/40001511

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

Thermal decomposition products of polypropylene

(2)

ANALYZED

NATIONAL RESEARCH COUNCIL OF CANADA DIVISION OF BUILDING RESEARCH

Ser TI-il N2lr2 no.

404

c. 2

BLDG

THERMAL DECOMPOSITION PRODUCTS

I

OFPOLYPROPYLENE

by

Y. Tsuchiya and K. Sumi

Reprinted from

JOURNAL OF POLYMER SCIENCE, A-1

Vol. 7, No. 7, July, 1969, pp. 1599-1607

Copyright @ 1969 by John Wiley &Sons, Inc.

I

N A T I D

..

41 R E S ~ A P C ~ I L O L I N C I L Research Paper No. 404

of the

Division of Building Research

Price 25 cents

OTTAWA June 1969

(3)

PRODUITS D E PYROLYSE DU POLYPROPYLENE SOMMAIRE

Les auteurs ont realis6 la pyrolyse du polypropylhne sous vide ?i des temperatures variant entre 350 e t 395OC, puis ont dhermink par chromatographie en phase gazeuse la nature des hydrocarbures obtenus de

C1

?i C9. Les auteurs Ctudient la formation des vingt produits volatils de d6colnposition les plus abondants en se fondant sur le r81e important que jouerait le transfert intramol6culaire d'un radical ?i Yetat libre.

(4)

Thermal Dccomyosi~io~i

P r o d ~ ~ c ~ s

o l Polyproyylenc

YOSILIO TSUCI-ILYII rid TiIliUO SUA'II, N u l i o ~ ~ ~ l Liescc~t*cll, C'ui~~~cil oJ'

Canada, Diuisior~ oJ L'u~lcli~rg licseu~.cl~, Ollaiou, Cui~aclu

Synopsis

Isotactic polypropylene was decomposed under vacuum a t 3G0, 380, and 400°C, nud the volatile products from CI to Clz llydrocarbons were analyzed by gas chromatography. The forn~ation of the main p r o d ~ ~ c t s is discussed on the basis of a free-radical mechanisnl in which intramolecular radical transfer is assumed to play an important role. The mecllanism of the formation of ,z number of products suggested by previous workers is criticized on the basis of the results of a more comprehensive annlysis of this inves(.i- gatioli.

l>c~c.ouil~ositio~i l~roducls of polypropylc~ic 11:~vc l~ccii dclcr~ilii~ccl bj

hcver:ll ilivcsligxtors ill order to explain tllc mcch:~nis~n of dccoiiipositioii of tliis polymcr. lladorsliy arid Straus' used insss spectronictry aiid analyzed ~ ~ r o d u c t s having one to six carbon atoms, but did not scparatc any isomers. Moiseev, Iihloplyanliina c t al., Bailey et al., and v:~n Schootcn and Even-

l i u i ~ ~ - ~ used gas chroinatography. hloiscev and his c o - ~ o r k e r ~ ~ ~ ~ r c - scnted a good picture of the mechanism of decolnpositioil by assuming intr:~-

molecular radical transfer. The chromatograms presented suggest, how- cvcr, t11:~t more precise experimental data could be obtained by using some newer techniques of gas cliromatography. Bailey4r%letermined the products from C1 to C;, hydroc:irbons a ~ l d explained the formation of the major fragments. van Schootcn and EvcrihuisC simplified the analysis by con- verting all the olefins to the paraffins and presented data in which the products having the same carbon slieletoii were combined. They extended the analysis to Clz llydrocarbons and presented a lncchanism of dccomposi- tion that was more coinl~rehcnsivc than tliose presented by others. The limitation imposed hy conl1,inilig tlic olclilis : L I I C ~ the p:wafIi~is precluded,

however, :L n1o1.c~ cu~iiplclc r x p l : ~ ~ i : ~ l i o ~ ~ ol' I11c iilccha~~isni.

'I'l~c aut1101.s ol' (lie ~)l.chsc,l~l l)aI,cxr 1)elicvc t11:~1 lilorcb co~iil~rcllc~~~sivc tll~ln in ~vliich tl ~ e 1):~raffilis :~ ~ i t l Lhe iutlividual ol(.li~~s :Ire S(\IJ:LL.:L~C~ s l i ~ ~ ~ l i l 1 ) ~ useful ill c-liscussing tlic ~ilcclianisnl of dcconil)ositiou of polypropylcnc. Products f1.0111 C1 to C12 hydrocarbons were analyzed by gas clirouiatog-

(5)

TSUCI-IIYA A N D SUM1

EXPERIMENTAL Material

A commercial gr:~dc of isotactic polypropylenc havii~g :L spcciiic gri~vity

of 0.905 ailcl a crystal nleltirlg point of 166°C was usccl. The sample was first treated with methyl ethyl ltetorie ill a Soxhlct cxtraction appnratus for 50 hr aiid dried under vacuum, to remove the ainolphous portion.

Thermal Decomposition r 7

1 he W ~ ~ I L ~ : L ~ U S k~lid procedure werc similar to tllosc usccl in tllc previous

studies oil p~lyisobutylenc.~ A horizoiltal quartz tube containing 1 g of si~lnplc was evs~cuatcd to 1 X l o p 4 nlin I-Ig. The vacuum line to the 1)ump \rus then closed, a i d an electric furnace provided with wheels was nlovcd quicltly itlolig steel trilclis to position the sanlplc in tllc hot zonc. The sample was pyrolyzcd a t 360, 3S0, and 400°C.

Analysis r 7

1 he gas chromatographic co~lditiolls that \\-ere used for the a~ialysis ~ ~ ~ c r c tlic same as in the previous studies.' 11 silica gel-paclictl col~unn alicl :L

s u ~ p o r t - ~ : ~ t c c l open t ~ ~ b ~ l i ~ r colulnu with sclualane : ~ s tllc liquid p11:lse were usctl with a flame ionizatiori detector.

RESULTS AND DISCUSSION Analysis of the Products

Tlic clcco~nposition products of polypropylene pyrolyxcd a t 400°C: :u.c prcsentctl in Figure 1. The relative nrcas of the pealts of the cln.omato- grams are rcpreseiited by line charts agailist the retelltion illdices both for the pyrolj~sis products and the hjrdrogenatcd pyrolysis products.

The clcconlposition products were composed of five different homologous hcrics as sho~vri iri Ir'igure 2. The products that die1 not belong to the\c scl-ics amounted to only 0.3% by weight of the products analyzed. Tlic iivc homologous series each protluced a straight line parallel to one another.

.I doublet corresponding to product a-3 (nrhich is three rnoriomcr units greater than the sm:lllest fragmcnt of series "a") was fouilcl in the chromatograms.

h

_doublet_{corresponding to product b-3 w:ls also found. vall}

Schootcll a i d EvenhuisQdentified a-3 as 4,6-dimcthyl1101li~ne aiicl the

hydrogenated product, of b-3 as 2,4,6-trin1etllylnol1:~ne by infrared and mass spect ronlctric :~i~:~Iysis. Tllcy :~shunictl t lint t hc two doublet s are

st crcoi.:oin(~r\. rrlw prcs(1i1t ( ~ s p t > ~ ~ i ~ ~ ~ e i ~ l ;II rosull h support t llc s ~ ~ g g c s t ion

th:~t, tlic clo~~l)lct\ arc tluc to stcrc~oisoiuc1rh. ,is i~iclic:~tctl cb:~rlicr, tllc rc- tcntioi~ iiltliccs o l tllc two cloul)lc(s fit tlic pohilioli\ ol' scrie.: :L : u ~ t l I), but,

(lid not fit ~~113' other ~erich ;1llc1 t~11cse ~ ) r o c I ~ c t s re cs~)ec(e(l fro111 a 1~1io1~1- eclgc of the mcchiulism of clccoinposition of polymers. The boiling pui~lt of :L-3, cstinlatccl fiom rdclltion iriclcs-boiling point data, was 17g°C, 1

(6)

A R E A OF P E A K S T A K I N G 2 , 4 - D I M E T H Y L - I - H E P T E N E AS 100

_-

AREA OF P E A K S r u e m w o 0 0 0 0 0 0 I N ARBITRARY U N I T S I I I I I I I I I I

-

0

-

methane

-

0 C3 0 0 rn

'

-1

:

p ~ o p y l e n e 0 0 ?= v W 0 - propane

s

O

I

2 0 Z w 0 D C VI penlane

7

8 - v) 0 2 - m e t h Ipenlane n

;

- F m e t h y ~ - I - p e n t e n e % w 2,4-dimelhylpenlane rn 9 -4 2.4-dimethyl-I-penlene < v

wl~crcns Illat of -4,Ci-di1i1ct11yh~o1~~~11~ fo1111t1 ill tlic litcraturc" \vas 179.S°C:.

Solic of tllc other saturated 11ydroc:wl)ons lluving boiling points of' 179.S =t

2.0°C liad the carbon ~ l i ~ l c i 0 1 1 c o r ~ ~ c s p o ~ i d i ~ ~ g to frngrllelits from poly- p r o p j ~ l e i ~ ~ . ~ A sinlilar method to support the identilicatio~i b-3 \\--us not rorlducted because of lacli of snfli(:icnt tlnt :L or1 comporilitls having boiling poinls ill thc raligc of 111:~t of I)-::.

Tlic. 1.cs111ts of tlic qu:~nlit:tli\.c\ :r~i:~lyhis : ~ r c ~)rc.scr~ictl ill l'al)lc I.

I I I I I I I I

-

propane

-

isabulane < 0 rn a o 2-methylpentane

-

4-methylheplane 2.4-d~melhylheplane

-

T

Z D

-

a m -

T h e mec1~:uiihm of decolnpobit,ion of polyprop3,lcnc is give11 in Scllelne 1 ; l l ~ e dccolnposilioli of' scco~ldary r:ldicallI only is slionr~l. Tllc initiatioli 1.c-

a I l l I I I I rn - 0 I \ I 0 -

(7)

.saa!pu! rro!luala.r .r!arl-) rrro.rj I)a)om!)sa a.ra.11 spunocl~uoo pay!lrrap!rm jo slq8!a.u JqnsaIoIg.

I 'Z

8 ' 6 1 P ' P G)ll[>!-<?J-O()T

001 ~ 0 . i 001 TP.1 OO1 MZI'O ~)az.ilcrrr: sa[!!i:lo.\ [c)o,T,

PP'O 9 9 0 ' 0 P'T C f 0 . 0 SL ' T f Z 1 0 ' 0 rrr.ro~ o.rrn.\'.ra 'arrarrou-~-~.ir[~ar~i!.r,~-~'f'~

9E'O I'CO ' 0 G ' T OfO'O $:L ' T O E T O ' O rrr.roj oa.rrll larrarrorr-~-~.ir~iarr~!.~ j,-9'f'z

9E.O ZC0 ' 0 GF'O f T 0 . 0 9 9 ' 0 Of 00 ' O ~ L I . I O J c~.rr~).C.ra lar~cri~~rr~.i~~]arri!([-~)ip

6 2 ' 0 Z f 0 ' 0 SE'O 1 1 0 ' 0 ~ c . 0 (iF:OO ' 0 rn.roj oa.rrr) 'anr:rrou[.irj~~r~~!([-$)~p

G E ' O f f O ' 0 EC.0 900.0 0 :[cad

4'L'O st30 ' 0 - 0 0 LOO'O TI :11;ac1

C' '

C'O 61'0'0 O Z ' ~ C O O ' O rrr :11:ad

O'ST 0Z'Z: Z'TT 97% ' 0 T 1, OfO'O arra-)darl-1-1.Zril,ax1~( I-f';

E.Z f Z ' 0 4"; ZC0 ' 0 9 ' 5 ZTO'O arrclc[arii.\"~ ~ a ~ y - p

S6'0 GS0'0 ZL.0 / T O ' 0 c:f ' 0 I i l O O ' O aua-)uacl-~-l.ir1i-7rrr!([-~

t E ' 0 ZEO ' 0 ZZ'O t-00'0 aur:-)uacI~.ir~:arr~!([-f'~

P'O iiT0 ' 0 Z ' 0 800 ' 0 L[ ?IE+I

P'I'T 61 ' 1 0 ' 9 1 GFZ ' 0 (i 07. ii10 ' 0 aualrrad-~-l.ir[la~y-z

1 6 ' 0 F L O ' O T ' T 110.0 L T

nnocr

' 0 ~ ~ I G ~ ~ I J ~ I . < I I ) a ~ y - z

EZ'O CT0'0 T 1 ' 0 ZOO ' 0 szr.u.cl prrc s.13 ' a r i a ~ r r d ~ ~ - ~

G'fZ Z9'T C ' 1E 1i;P'O 9 ' 1 :.: TO1 ' 0 arru)rraC1

% T ' 0 SOO'O arralrrad-1

G T ' 0 0 1 0 ' 0 f-T ' 0 TOO ' 0 a r r a ~ ~ ~ r { - ~ - i . < r ~ ] a ~ < - ~

L O ' O fOO'0 ti0 ' 0 100 ' 0 arrv]rra

O ' F 91 ' 0 9 . 9 rig0

o

I ' ' !: ::so0 ' 0 a T i a ~ . < ~ l l c { o ~ ~

F'TZ S S ' 0 Z'ST IC1 . O .! 1'1 D(iC0 . 0 a1i~11.irl11.1~1

G ' T Y L O ' O 1 . 1 1ZOO'O aiiudo.r~

S ' P FT '0 y'c,' 05:O ' 0 Z ' f 11'00 ' 0 a ~ i t : r ~ ] > ~

(8)

0 1 I I I I I 1 0 I 2 3 4

M O N O M E R U N I T

Lcig. 2. I:olc111,io11 iil~lcs oT ~)l.otl~~c,ls: (D) itlcr~t.i~ietl l,o:~k; (E) il~~itlc~~lifietl peak.

Tr:lrlsfer to n t h c:~rbo11

Arnotuit of p r o d ~ ~ c ( ,

1)ecomposit ion mole-!.; uf

I"YOIII 11 1)roduct volntiles

-

Scco1ltl:lr). ~ : L ~ I C I L I :i I(;( I1:lllc 'L S

:I "-Arc( h~ I-1-pcnlcr~c 1.1.4 CII-CII~-~'I I I 1 5 lJcrl t a r ~ e 2 1 2 CIIJ CII, ) 2,~4-1)1111cthyl-l-11c11~~11c Lh !) 7 .I-Xlethylheptar~c 2 :; 7 2,.l,Ci-TI ~ ~ t ~ e t h y l - l - r ~ o ~ ~ c ~ ~ c 0 SO i) 1,ti-Dinleth) 111o11nrle O 6-5 P r i u ~ : ~ r y rutlic:il -4 I'ropz~r~e 1 . 9

-CEI-~II?-<;II-(~ [I, (1. 2,-l:-l'~itnel,l~yl-l-~~c1~ L ( ; I I ~ 0 . 9 s

I

CBn CIl:) Ci 2-.lIe~l1yl~)e11~:i11e 0 . 93 (i &~L,G-Triineth)-I-l-I1e11Ie11c 1 S L',.l-lIin~cLk~yll~cI,l:~~~c < O . I . - - 1% Rot, ( l c l e r ~ ~ ~ i ~ ~ c d .

(9)

'I'SUCIIIYA A N D SURII

C I

a-u

(10)

:~ctioii (A) occurs by rniicloni scission of the main chain, yielding t \ \ ~ o types of radicals: primary (I) and secondary (11). The production of radical I1

is more favorable than the production of radical I during the decomposi- ti011 because the former is also produced by intermolecular and intranio- lecular radical transfer to tertiary carbon followed by P-scission (B, C, Dl and E ) .

Intramolecular radical transfer and propagation (G) reactions can ~ ~ c c o u n t for the production of most volatiles. The quantitative results of the products formed a t 400°C are presented in Table I1 by assuming the occurrence of intramolecular radical transfer. T h e experimental results indicate that the radical transfer was mainly to tlie tertiary carbons. The :tmounts of the products formed following radical transfer to the prinzary and secondary carbons were small; these reactions were therefore neglected iii preparing Table 11. The ease of radical transfer to the tertiary carbons illcreases the amount of radical I1 3s compared ~vitli radical I . Thus, the arnouiits of products formed from radical I1 were much greater than those from radical I.

Stereoisomers were found in the decompositiorl products of isotactic polypropylene. The presence of some stereoisoincrs in tlie products car1 be explained by stepwise radical transfer, as slio\vn in Scheme 2, for the

.CII-CIIJ C:lI,-C11 CII, C:IIL-CI13

CIII CII? I CII? I CII,

I

\ ; * c I I ! IIC*-CIIJ

I

Il(;*-(:II, I IIC*-CII,

I

CII; CII, I CII? I (>I12 I

I I

@1:*-ClI,

-

c - C I I , + 11,c-(;*II

+

IIc*-C:II, I

I (>I12 (:I I 1 2 I IIC:*-CII, [IC*-C;I I

r3

d . . . J - - - CII, (:I12 I I . $;-(;LI, 2

formation o l 4,0-dimctliylr~o11t~11c, wlicre the asterisks clciiote asymmetric carbons. The occurreilce of stepwise radical traiisfer during the thermal decomposition of polylnethylerle has been reported earlier.g

Equal mounts of the threo and erythro structures should be expected from stcpwise radical transfel.. The cxpcrimcntal results s l l o ~ ~ ~ c d tl1:tt tlic latter pc:~li of tliis doublet wa5 al\vays greater th:tn tlic fornlcr. T11ih hug-

(11)

1606 TSUCIIIYA AND SUM1

talicn pl:lcc, arid that the former peak is due to thc tlireo and thc lattcr to the crythro st,rl~cl w e .

Thc analytical data of the hydrogcnatcd clccomposition products ob- lt~incd by vaii Scllooteil :111cl EvcnhuisB agrccd wcll with t11c cxpcrimcntal results of t11c present, invcstigntion. By separating the iridiviclual olcfiiis from tlie pnrafliiis, thc prcscnt authors mere able to obtain a bctter under- star~tlir~g of tlic mcchnnism of c1ccomy)osition of polypropylene.

vnri Scllootcn : ~ n d Evcnhuis suggcstcd llircc clifrc~rcnt roulcs for [ I N : So~.rii:~tio~~ of ?-~i~cthyll)c~iI:~llc ill tlie 113-drogc~n:~tccl products: t\vo for 2-r1ic~lliylpclit:~rie prior to 1iydrogcn:~lioli :~ritl olic for l-mc:tllyl-l-j)clitc.~~(:.

111 llic prcscril, cspcrimclils hot11 of lllcsc procluoth mcrc fount1 to 1)c ~ n i n o r ollcs. 'Llic r i ~ ~ ~ i l i product, wit 11 1 lie c:~rl)o~i slL(~l(~l 011 of 2-nicll1~~lpc~~il:~~ic JV:LS

2-rnctlij,l-l-l)cntcnc, wliicli could bc formc~l 1)y i ~ i l ~ : ~ m u l c c ~ ~ l i ~ r radical

I r:~rislcr from a secondary macror:~dic:~l (11) to l l ~ c third cnrbon (which is tertiary) followed by /3 scission.

van Schooteri and Evcrihuis belicvcd tli:~t 2,4-c1imethyl~)cnt:~nc is ail inlportallt product formed by a radical trnnsfcr from a primary macro- r:~dical (I) to a secondary carbon, follo~ved by /3 scission. I n the present cspcrimcnts the amount of 2,4-dimethyl-1-pentenc nr:ls found to be much greater than the paraffin having the same carbon slielcto~l. This olefin could be produccd by a radical transfer from a primary m:zcroradical (I) to tllc fourth carbon of the chain (which is tertiary), followed by

P

scission.

van Schooten a l ~ d I<vcl~huis suggcstcd five different routes for thc fo1.m:~- tion of 2,4-dimethylhcl)t:lne. They believed t,11at two of these routcs lead- ing lo the for~natioll of 2,4-clin~ethyl-1-heptelle arid 4,G-dimet11yl-2-heptcnc n7erc the inlportant ones. T h e present expcrin~cnts showed that only thc former olcfin is a major product; the latter was less than 1 pcr cent of the formcr.

T h e above exainplcs illustrate the advantage of separating individual products in order t o explain the mechanism of thermal decomposition of ~)olymers. van Schootcn and Evenhuis neglected radical transfer to tllc third and fourth carbons of the polypropylene cl~ain, which is important, as shown in Table 11. Also, Ihey ~ ~ ~ e r c not a ~ ~ ~ a r e of the greater yield of products from the secondary macroraclical (11), as compared with t h a t from tllc primary (I), as this was not apparent from their experimental data.

I<hloplyanlii~la et 2 ~ 1 . ~ found large amoullts of 1-pcntene and 2-pentenc in the clccompositio~l products of polypropylene. They attributcd t h e formation of these two products to intramolecular radical transfer from sccondnry nlncroradical (11) to primary carbon and to secondary carbon, respectively, followed by /3 scission. I n the present experiments, only small amounts of pentenes were found. This result is consistent with over- :dl clat:~ obtair~cd in that the product s that were formed after radical transfer to t lie primary arlcl s(~corid:~ry c:~rl)o~is w e r ~ foul~d ill small a n ~ o u ~ i t s .

13:tilcy ct, al.",' l o ~ ~ l i t l 1:~rgc: :~rlioulits of 1)rop:~11(', ~sl)(\ci;~LIy at low pyrolj sis i r ~ l ' l i ~ y r cspli~incd lliis rch~ilt 1)y suggcsting tlic ~ ) ~ C S C I I C C or

(12)

heacl-to-11e:~d structurcs in Ihcir polymcr samplc. According lo tlle prcscnt linonrledge of the lncchnnisn~ of clccon~posilion of polymers, al)l)roximatcly cqnnl a ~ n o u n t s of 2-mctllyl-1-llcsr~lc and prop:Lnc sliould 1)c p1.oducccl by the n~echunisln :

T h e prescnt authors 1)clieve Ihat it is ncccssary to determine the r~mourlt of 2-methyl-1-hexene produccd to conlirm that the irregularity in the polymel. suggested b y Bailey xvas the main reason for the large yield of propane. I n the present expcrimcnts, a smallcr amount of propane was found and thc amount of 2-methyl-1-hcxcne a t a retention index of 67s was less t11:ul one- tenth of the amount of propane.

AiIadorsliy presented a mecllanism of decomposition whereby scission of a C-C bond in the chain is accompanied by a transfer of hydrogen a t the site.I0 According to this mechanism, a saturated end and an un- saturated end are produced in cclual amounts. If volatilcs were produccd b y this mechanism, allianes, alkenes with a. terminal double bond, and allradienes with two tcrminal double bonds should be produced in the ratio of 1 :2: 1. T h e prcsent rcsults do not agree with this mcchn~iis~n bccause only small amounts of alliadienes were found.

References

1. S. 3Tadorsky aritl S. S l r i ~ ~ ~ s , J . I?es. Nut. h'i~r. Slar1,(1., 53, 361 (1934).

2. V. D. hfoiseev, I'laslicheskie ill(tssy, 19(i:3, No. 12, 3; I.<n;lisli (,r:~nsl., Sonirl. IJla,slic.s, 1964, No. 12, 6.

3. 3.1. S. Khloplynnkina, 31. B. Nienlnn, mltl V. D. h,Ioisecv, I'lasliclreskie ~ll(t.s.r!/, I O G l , No. 2, 9; Eriglish traiisl., Soviet Pklslics, 1962, KO. 2, 11.

4. W. d. Bailey and C. N. Lieske, paper presented to 1)ivisioii of Polynler Chcruist~~y, A~uericnn Chernicnl Society >Ieet,ing, (New Yorlr) 1963; I'reprir~ls, 4, No. 2, 3S9 (19ti:l).

5. W. J. Bailey and C. L. Liottn, paper present,ed to LXvision of Polyrner C~he~riislr~y, Amerie:~n Chernieal Society Meeting (Chicago), 1964; I'/~ep~.inls, 5, Nu. 3, 33:; (IO(i4).

6. d. van Schooten and J. I<. Evenht~is, IJoly/ner, 6 , 3 1 3 (1965). 7. Y. Tsuchiya arid I<. Su~ni, J . Polyrn. S d . A-I, in press.

8. S. W. Ferris, Handbook of Il!/drocnrbons, Acadenlic l'ress, New \.'orlc, 1960, pi). 53-55.

9. Y. T s ~ ~ c h i y a : ~ n d I<. Srimi, J . Pol?jrn. Sci. U, 6 , 357 (196s).

10. S. L. bladorslcy, l'lrarrntrl L)eyrtrtlnliot~ of Orqc~nic Polylners, Ir~lcrsc:ie~~c:e, N e w York, 1964; p. 117.