HAL Id: jpa-00224332
https://hal.archives-ouvertes.fr/jpa-00224332
Submitted on 1 Jan 1984
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
A. Dremin, L. Babare
To cite this version:
A. Dremin, L. Babare. ON THE SHOCK POLYMERIZATION PROCESS. Journal de Physique
Colloques, 1984, 45 (C8), pp.C8-177-C8-186. �10.1051/jphyscol:1984832�. �jpa-00224332�
JOURNAL DE PHYSIQUE
Colloque C8, supplément au n'il, Tome *5, novembre I9&t page C8-177
ON THE SHOCK POLYMERIZATION PROCESS A.N. Dremin and L.V. Babare
Institute of Chemical Physics (Branch), USSR Academy of Sciences, Moscow Region, Chernogolovka 14Z4Z2, U.S.S.R.
Résumé On certain nombre de composés polymérise sous l'action d'une onde de choc, le processus de polymérisation de certains monomères a
lieu le temps d'action du choc (^10~
6sec). Le but du présent travail est d'établir une comparaison entre les conditions,pression-température, de polymérisation sous pression statique et dynamique. L'étude a été effectuée avec le trioxane qui polymérise pendant la durée du choc ; sous pression statique la polymérisation de ce composé est fortement dépendante de la pression et de la température. Il a été établi que le processus de polymérisation, qui prend effet pendant le choc, est réglé par la mobilité non thermique et par la déformation des molécules de trioxane dans le réseau cristallin.
Abstract It is known that a number of various compounds are polymerized under the shock wave effect, the polymerization process of some mono- mers proceeding during the shock action time (~10~6 sec) . The purpose of the paper is to reveal whether the shock polymerization process reg- ularities come to the same pressure and temperature influence which takes place at the static conditions. The investigation has been carri- ed out with trioxane which polymerizes in time of the shock effect and its polymerization process depends strongly on pressure and temperature at static conditions.lt has been found out that the nonthermal mobility and the deformation of the trioxane molecules in the crystalline lattice regulates the process under the shock effect.
In 1964 the effect of organic monomers polymerization under the shock waves was discovered in the Institute [1-2]. It was found out
that a number of various compounds in liquid and solid states were polymerized under the shock wave effect. The polymerization process can proceed with various types of chemical bondsi double CsC bond (acrylejnide, styrene); triple CsC bond (tolane); triple CsH bond (acrilonitrile); double CmO bond (bensaldegyde); revealing heterocyc- les (trioxane, tetrahydrofuran) 1.3,4]. Some compounds which are hard polymerized due to ateric effects were polymerized under the shoclima- leic anhydride, oil acid nitrile, • * * ) •
The shock wave polymerisation proceeds without any catalysts commonly used to initiate the process at normal conditions £2,4 1 . The active centers are created by the shock wave, they originating mainly inside of the shock front [5]. The next polymerization pro- cess stage - the polymerization chain growth can proceed either du- ring the shock wave effect [6} or after the shock passing [7). It depends on the monomers physico-chemical properties*
The shock compression of any substances results in pressure and temperature increase* Pressure and temperature have a considerable influence upon the polymerization process at normal conditions* The
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984832
purpose of t h e paper is t o r e v e a l p r e s s u r e and temperature i n f l u e n c e on t h e polymerization process under t h e shock wave l o a d i n g c o n d i t i o n a The a v a i l a b l e d a t a concerning t h e problem a r e contraversy. It has been found o u t t h a t t h e change of t h e sample i n i t i a l temperature from -195OC up t o +25OC does n o t i n f l u e n c e t h e polymer y i e l d f o r t h e shock polymerization of c r y s t a l l i n e acrylamide p,8]. It follows from t h e d a t a t h a t t h e process r e g u l a r i t i e s does n o t reduce t o summary pressu- r e and temperature e f f e c t [2,8,9]. However, t h e d a t a of [7,10,113 c o n t r a d i c t t h e statement. The i n f l u e n c e of t h e acrylamide samples i n i - t i a l temperature on t h e shock polymerization process h a s been obser- ved i n t h e s e papers.Besides, i t has been shown i n [7,11] t h a t t h e c r y s t a l l i n e acrylamide shock polymerization can proceed according t o t h e thermal explosion mechanism, a c o n s i d e r a b l e p a r t of t h e process t a k i n g place a f t e r t h e shock passing. It has been found o u t i n \ 4 ] t h a t t h e acrylamide shock polymerization occurs o n l y a t t h e s t e p p i n g shock l o a d i n g o f t h e sample, a s i n g l e shock does n o t p r a c t i c a l l y g i v e r i s e t o t h e polymer o r i g i n . A t t h e s t e p p i n g shock l o a d i n g t h e o t h e r r e a c t i o n s , except t o t h e acrylamide polymerization, t a k e p l a c e and i t causes t h e appearance of t h e c r o s s l i g h t i n g polymer. This f a c t hampera one t o determine t h e polymerization process k i n e t i c c h a r a c t e r i s t i c s
[12, 131. It followe from t h e above mentioned t h a t t h e c r y s t a l l i n e acrylamide i s n o t s u i t e d t o t h e i n v e s t i g a t i o n o f p r e s s u r e and tempe- r a t u r e i n f l u e n c e on t h e shock polymerization process. To s o l v e t h e problem one needs some monomer which must be capable t o be polymeri- zed i n time of shock wave p a s s i n g and has no acrylamide d i s a d v a n t a g e s
Monocrystalline t r i o x a n e has been s e l e c t e d a s t h e monomer. Unli- ke acrylamide, t r i o x a n e is polymerized i n time of s i n g l e shock e f f e c t [4,6]. The polymer o r i g i n a t e d is l i n e a r and e n t i r e l y s o l u b l e . These p r o p e r t i e s enable u s t o determine l e n g t h and q u a n t i t y o f t h e polymer chains. The polymerization process i s completely defined by t h e para- meters. Trioxane molecules r e p r e s e n t six-termed c y c l e s w i t h a l t e r n a -
t i n g C and 0 a t o m . The c y c l e s a r e s t e r i c a l l y a p r o p r i e t e l y arranged i n t h e c r y e t a l l a t t i c e t o j o i n each o t h e r (fig.1 f . The c h a i n i n c r e a s e process i s governed by t h e c r y s t a l l a t t i c e . The process can proceed along C and A c r y s t a l l o g r a p h i c axes [14,15]. The c r y s t a l l a t t i c e of t h e o r i g i n a t e d polymer corresponds t o t h a t of t h e monomer. The growth of t h e chain has time t o accomplish i n t h e p e r i o d of t h e shock e f f e c t [6]. These s t a t e m e n t s a r e supported by t h e f o l l o w i n g experimental data:
1. t h e polymer c h a i n l e n g t h depends on shock s t r e n g t h and duration.
2. t h e polymer c h a i n s conformations depend on t h e c o n d i t i o n s of shock wave loading: a ) on shock wave e f f e c t d u r a t i o n , b ) on s i n g l e o r s t e p - ping shock e f f e c t , c ) on monocrystal sample a x i s o r i e n t a t i o n r e l a t i v e t o t h e d i r e c t i o n of shock wave f r o n t motion.
IR-spectrum a n a l y s i s h a s shown t h a t t r i o x a n e molecule s t a t e and l o c a t i o n govern t h e chain conformation of t r i o x a n e polymer. Both t h e s t a t e and l o c a t i o n a r e f i x e d i n s i d e of t h e c r y s t a l l i n e l a t t i c e a t t h e process of t h e polymer c h a i n i n c r e a s e i n time of shock wave e f f e c t . The conformation o r i g i n a t e d i s metastable. It i s e a s i l y annealed un- d e r t h e a c t i o n of u l t r a s o u n d , a t m e l t i n g and r e c r y s t a l l i Z a t i o n . The conformation annealed approximatqs t o t h e c a l c u l a t e d conformation of t h e u n s t r a i n e d chain.
The d a t a o b t a i n e d on t h e monomer molecules s t a t e d u r i n g t h e i r
j o i n i n g t o t h e i n c r e a s i n g c h a i n permits one t o undemtand t h e f e a t u -
r e s of t h e mechanism involved i n polymerization process i n shock
Pig.1. a ) Transition of monomer-trioxane i n t o polymer-polyoxime- thylene, b ) The scheme of polymer chain formation i n c r t a l l i n e trioxane, c ) C s t a l s t r u c t u r e s of trioxane (1Yand 801 yoxime thylene (3. I n t e r n a l d i e tances a r e g i - ven i n A .
waves. It should be noted t h a t due t o the low value of the trioxane polymerization h e a t the c h a r a c t e r i s t i c s of the o r i g i n a t e d polymer a r e not d i s t o r t e d (e.g. the polymer chains y i e l d , length and conformationb I n the case of acrylamide polymerization the t r a n s i t i o n of the C=C
double bond t o the C-C s i n g l e bond i e accompanied by the emission of 15 kkal/mol and i t r e s u l t s even i n the thermal explosion. Unlike ac- rylamide, the trioxane polymerization proceeds through breaking the C-0 bond of the monomer cycles and c r e a t i o n of the same kind of bond among the neighbouring molecules p r a c t i c a l l y without emission of e n e r t3Y
The j o i n i n g of trioxane molecule open cycle t o the increasing chain i s accompanied by some r o t a t i o n . The formation of the s p i r a l - l i k e polymer chain i n the process gives r i s e t o the c r y s t a l l a t t i c e knot displacement. I n t h i s d i r e c t i o n the c r y s t a l configuration beco- mes somewhat longer. A t c e r t a i n etage of t h e chain growth process the
s t r e s s i n the polymer c r y s t a l l i n e l a t t i c e appears and supresses the
process [IT]. It means t h a t i t i s necessary f o r the polymer chain
growth some mobility of the monomer moleculee. 'Fhe mobility provides
the moleculee turning and the r e l e a s e of t h e c r y s t a l l a t t i c e s t r e s s .
The polymerization process of the c r y s t a l l i n e trioxane depends
s t r o n g l y on temperature a t normal conditions [18,191; t h e temperature
decrease down t o -lO°C suppresses the process e n t i r e l y . But the phase
transition is not involved in suppressing the process, since there is not any phase transition in the temperature interval -170°C + +64OC.
The suppression process at -lO°C is due to the intermolecular distan- ces shortening and hindering all kinds of molecule motion. At -170°C trioxane crystal lattice has maximum rigidity. In the temperature in- terval +25OC + +55OC the intermolecular distances and the molecules mobility increase considerably. According to NMR data the change of the configuration of the monomer molecules and their orientation mo- tion are possible in this temperature interval [20,21\. The polymeri- zation process proceeds most rapidly at these temperatures. The tempe- rature increase from + 25OC up to 55OC (premelting temperature) re- sults in the polymer yield increase of approximately in an orderL141.
The static pressure effect decreaaesthe mobility of the molecu- les and the intermolecular distances and hampers the trioxane polyme- rization process \22,23,241. The above mentioned pecularities of the trioxane solid phase polymerization process makes the monomer rather suitable to investigate the problem involved- The polymerization pro- cess ie rather strongly subjected to temperature and pressure with opposite effects. Changing the temperature of the initial samples crg.
eta1 lattice at various pressures of shock wave loading one can ex- pect to determine the proper role of pressure and temperatue separa- tely.
The shock wave experiments have been performed at initial tempe- ratures of the samples equal to -170°C, +25OC and +55OC. The crystal lattice mobilities differ strongly at these temperatures. A11 the ex- periments have been carried out with monocrystal samples of C-axis perpendicular to the shock wave front to eliminate the trouble in the size and anisotropy influence on the polymerization process. Table 1 has the characteristics of the polymers: the yield, the polymer ave- rage molecular mass and the quantity of the polymer chains. The expe- rimental set-up is shown in fig.2. The data correspond to the effects Table I*
Po P e r chLns number
I
- -
-
0.2.10~~
0.97*10~~
3 . 1 6 ~ 1 0 ~ ~ 0.65*10~~
s empl e initial tempera- ture
*oC -170 -170 -170 +25 +25 +25 +55
pressure P GPa
3.3 3.9 5.5 30 3 3.9 5. 5 3.3
1 0 . 0 12-80 1 588 1 ? + 4 9 * 1 0 ~ ~ samples partially melt
%
*lo-3
- - -
628 408 228 780 +55
+5 5
yiel
3.9 5.5
-
0.17 1.5 1.5 4.5 8.2 6.1
- -
-
2.95
2-22
1.51
3.45
Pig. 2. Experimental s e t-up. (The ex- p l o s i v e charge i s i n t h e c o n t a c t w i t h t h e ampule's t o p ) . a ) S i n g l e shock wave p a s s i n g through t h e sample, b ) S t e p p i n g shock waves l o a d i n g , w i t h shock waves r e f l e c - t e d from t h e bottom and t o p o f t h e ampule. 1 - t h e g e n e r a t o r of plane d e t o n a t i o n waves; 2 - t h e
e x p l o s i v e charge; 3 - t h e ampule o f r e c o v e r y (copper). The i n t e r n a l and e x t e r n a l s i z e s 30 mm and 50 mm. 4 - t h e sam- p l e ; 5-the l a y e r of Pb; 6 - guarding r i n g s ( s t e e l ) . of t h e s i n g l e shocks of 3.3 - 5.5 GPa. A t t h e p r e s s u r e s h i g h e r t h a n 5.5 GPa t h e recovered samples begin t o m e l t but a t t h e p r e s s u r e s l o - wer than 3.3 GPa t h e polymer y i e l d i s n e g l i g i b l e small.
I n t h e p r e s s u r e i n t e r v a l a t -170°C t h e p o l y m e r i z a t i o n p r o c e s s i s almost e n t i r e l y suppressed. Even a t maximum p r e s s u r e 5.5 GPa t h e poly- mer y i e l d i s e q u a l o n l y t o 1.5%. The r a t e of t h e p r o c e s s i n c r e a s e s a t +25OC,and a t +55OC t h e polymer a l l c h a r a c t e r i s t i c s amount t o t h e i r m a x i m u m values. I n a d d i t i o n t o t h e temperature e f f e c t on t h e polymer c h a r a c t e r i s t i c s mentioned, t h e change of t h e i n i t i a l samples tempera- t u r e r e s u l t s i n t h e f o r m a t i o n of t h e polymer c h a i n s of d i f f e r e n t con- f o r m a t i o n s . Fig. 3 shows t h e IR-spectra of two polymer samples. They have been o b t a i n e d a t t h e same s i n g l e shock l o a d i n g of 3.5 GPa b u t a t v a r i o u s i n i t i a l temperatures: -170°C and +25OC. The spectrum i n t e -
800-1200 cm c h a r a c t e r i z e s t h e c h a i n conformation s t a t e . A t
-170°C more narrow and i n t e n s i v e bands of a b s o r p t i o n ( 1 ) a p p e a r i n
t h e i n t e r v a l . A t +25OC t h e bands become wider (2). It is obvious
t h a t t h e r e a s o n f o r i t i s t h e i n c r e a s e of d i s t r i b u t i o n of t h e a n g l e s
v a l u e s of t h e molecules c y c l e s i n n e r t u r n s . It means t h a t t h e c h a o t i c
displacement o f t h e monomer molecules r e l a t i v e t o t h e C r y s t a l l a t t i c e
k n o t s i n c r e a s e s . The displacement i s c h a r a c t e r i s t i c of t h e thermal
m o b i l i t y . This s t a t e of t h e monomer molecules is f i x e d a t t h e p r o c e s s
of t h e polymer c h a i n growth. The m e t a s t a b l e conformatione ( 1 ) and
( 2 ) a r e e a s i l y annealed. The IR-spectra of t h e s e b o t h samples become
completely i d e n t i c a l (3) a f t e r t h e t r e a t m e n t o f t h e samples by u l t r a -
sound low frequency d i s p e r s e r i n l i q u i d p a r a f f i n . The spectrum ( 3 )
does n o t c o n t a i n t h e bonds c h a r a c t e r i s t i c of t h e samples s u b j e c t e d
t o t h e shock wave t r e a t m e n t . Thus, a c c o r d i n g t o t h e experimental da-
t a t h e temperature h a s some i n f l u e n c e on t h e t r i o x a n e polymerization
process which t a k e s p l a c e i n time of t h e shock wave e f f e c t . However,
t h e sample i n i t i a l temperature i n f l u e n c e i s c o n s i d e r a b l y weaker i n
comparison w i t h t h a t a t t h e s t a t i c c o n d i t i o n s . Hence, a t normal con-
d i t i o n s t h e temperature i n c r e a s e from +25OC up t o 55OC r e s u l t s i n t h e polymer y i e l d i n c r e a s e by an order. A t t h e s i m i l a r temperatures but a t t h e shock wave l o a d i n g t h e polymer y i e l d i n c r e a s e s only two time&
It means t h a t t h e pressure reduces t h e temperature influence. I n spi.
t e of t h i s f a c t , t h e i n c r e a s e of t h e shock amplitude, n e v e r t h e l e s s , r e s u l t s i n t h e polymer y i e l d growth. Probably, a h i g h e r temperature of t h e shock-compressed samples under s t r o n g e r shock e f f e c t is res- ponsible f o r t h e r e s u l t .
Fig.3. IR-epectra of polymers (polyoximethylene) obtained by s i n l e shock loading up t o 3.9 GPa a t -170°C(I) and a t 4
+25 C ( 2 ) . A f t e r recovering the both samples give ( 3 ) . The experiments with t h e s t e p p i n g shock loading of t h e samples have been performed t o r e v e a l whether r e a l l y t h e shock compression temperature does e f f e c t on t h e polymerization process. A t t h e s t e p - ping loading t h e f i n a l pressure i s gained by consecutive pass t h r o w the sample of some shock waves. A t the same f i n a l pressure t h e sub- s t a n c e f i n a l temperature of t h e s t e p p i n g compression i s lower than i n t h e c a s e of t h e s i n g l e shock. Pig.2b shorn t h e experimental s e t - up. The d a t a ( s e e t a b l e 1 1 ) i n d i c a t e t h a t t h e samples have lower h e a t i n g a t t h e s t e p p i n g loading i n comparison with t h a t a t t h e s i n g l e shock. Thus, a t t h e sample i n i t i a l temperature +55OC under t h e s i n - g l e shock of 5.5 GPa the sample p a r t i a l l y melts but a t t h e s t e p p i n g loading up t o h i g h e r pressure of 7.0 GPa t h e sam l e does not m It a t
a l l . The experiments with both types of loading gave been c-led out a t t h e samples i n i t i a l temperature of + 25OC t o e l i m i n a t e t h e i n f l u - ence of t h e samples melting (table111). It has been found o u t t h a t a t t h e s t e p p i n g loading t h e polymer y i e l d i n c r e a a e s i n s p i t e of t h e temperature decreasing and t h e f i n a l pressure increasing. A t t h e e t e t i c conditions t h i s change of the temperature and t h e pressure would have t o hamper t h e process. Thua, the d a t a i l l u s t r a t e the f a c t t h a t pressure and temperature a r e not t h e only r e s p o n s i b l e agents f o r t h e s t i m u l a t i o n of t h e trioxane shock polymerization process.
To r e v e a l t h e s p e c i f i o n a t u r e of t h e shock wave l o a d i n g the ex-
periments with various f i n a l pressures of t h e s t e p p i n shock loading
a t varioue i n i t i a l temperatures (-170°C, +25OC, + 5 5 0 ~ f of t h e a m p -
l e e have been performed. It ha8 been found o u t t h a t t h e samples
i n i t i a l temperature e f f e c t s considerably t h e polymerization process
both a t t h e s t e p p i n g and t h e s i n g l e shock l o a d i n g of r a t h e r low
pressure (1.8 GPa f o r t h e f i r s t shock). Thus, t h e process i s prac-
t i c a l l y suppressed a t -170°C and t h e polymer y i e l d i n c r e a s e s a t
Table 11*
---
+25OC and e s p e c i a l l y a t +55OC. The d i f f e r e n c e of t h e polymer c a r a c t e - r i s t i c s o b t a i n e d a t varioua i n i t i a l temperatures of t h e samples dec- r e a s e s w i t h t h e p r e s s u r e i n c r e a s e t o 3.3 GPa f o r t h e f i r s t shock. The 5.9% polymer formation even a t -170°C i n d i c a t e s t h a t some molecular s t a t e came i n t o being. This m o l e c u l a r s t a t e s u p p r e s s e s , t o some ex- t e n t , t h e i n h i b i t o r y e f f e c t o f t h e sample i n i t i a l temperature. I f p r e s s u r e i n c r e a s e s t o 3.9 GPa, t h e samples i n i t i a l temperature e f f e c t on t h e polymer c h a r a c t e r i s t i c s d i s a p p e a r s completely. It f o l l o w s from t h e d a t a t h a t t h e i n i t i a l temperature i n f l u e n c e i s weaker a t t h e s t e p p i n g l o a d i n g i n comparison w i t h t h a t a t t h e s i n g l e shock e f f e c t .
The r e v e a l e d s p e c i f i c f e a t u r e s of t h e s t e p p i n g l o a d i n g show t h a t t h e molecules s t a t e , governing t h e p o l y m e r i z a t i o n process under t h e shock e f f e c t , i s n o t confined t o t h e i r thermal m o b i l i t y only. The com- p a r i s o n o f t h e conformation o f t h e polymers o b t a i n e d a t t h e s t e p p i n g and t h e s i n g l e shock l o a d i n g a l s o s u p p o r t s t h i s conclusion.
sample i n i t i a l tempera- t u r e T C
* 5 5
+25
To e l i m i n a t e t h e e f f e c t of t h e i n i t i a l thermal m o b i l i t y of mole- c u l e s t h e experiments have been performed a t t h e samples i n i t i a l tem- p e r a t u r e -170°C. R a t h e r narrow and i n t e n s i v e bands o f a b s o r p t i o n ap.- p e a r i n t h e IR-spectrum i n t e r v a l 800-:I200 wi a t t h e s t e p p i n g l o - a d i n g ( f i g . 4 1 , while t h e o r i g i n of t h e molecule c h a o t i c thermal mobi- l i t y would g i v e r i s e t o t h e broadening of t h e a b s o r p t ' o n bands. Mo e- o v e r , some new a b s o r p t i o n bands (955. 1135. 1155 m ~ - ~ f appear in t2;e
I
f i r s t pres- e w e PI GPa
5.5 3.3 5.5 3.3 shock
l o a d i n g type
s i n g l e s t e p p e d s i n g l e s t e p p e d
i
I I I I
800 I000 1200 ?i, cm-'
Fig.4. IR-spectra of polymera ( olyoximethylene), o b t a i n e d by s t e p p i n g ( 1 ) and s i n g l e f a ) shock l o a d i n g a t t h e i n i t i a l temperature of t h e sample -170°C. The f i n a l p r e s s u r e a t t h e s t e p p i n g and s i n g l e shock l o a d i n g are 7.0 GPa and 4 GPa, r e s p e c t i v e l y .
f i n a l pres- s u r e Pf GPa
5.5 7.0 5.5 7.0
y i e l d * [ ? I
samples p a r t i a l l y melt 12.5 3.92 955 1 . 1 4 * 1 0 ~ ~
\
8.2 11.5
Polymer c h a i n s number l /cm3
1.51 3.80
208 924
3 . 1 6 * 1 0 ~ ~
1 . 0 1 ' 1 0 ~
Table 111*
* 1. R e s u l t s presented i n a l l t h e Tablea a r e averaged o v e r two- t h r e e a n a l o g i c a l t e s t s . 2. Percentage of t h e y i e l d (weght) a r e c a l c u l a t e d p e r i n i t i a l mass of monomer i n t h e ampule.
Unreacted p a r t o f t h e monomer is drawn away by vacuuming.
3. M,, i s t h e polymer average-viscosity
.molecular
.mass c a l - c u l a t e d by t h e formula 171 = 4 . 4 ' 1 0 - ~ ~ Oebb [26], where
- t h e c h a r a c t e r i s t i c v i s c o s i t y de tzrmined viscosime t- r i c a l l y . Dimethylformamide i s used a s t h e s o l v e n t a t T =
o
150°C, w i t h diphenylamine being of s t a b i l i z e r .
PO p e r
1c h i i n s number 1 /cm3
-
0 . 1 2 ' 1 0 ~ ~ 0 . 2 4 ' 1 0 ~ ~ 0*58*1017
IR-spectrum i n t e r v a l . The bands appear o n l y a t t h e s t e p p i n g l o a d i n g and a r e c h a r a c t e r i s t i c o f t h e m e t a s t a b l e conformation. The conforma- t i o n t e s t i f i e s t o t h e i n c r e a s e of t h e monomer molecules deformation s c a l e i n time o f t h e i r j o i n i n g t o t h e chain.
+25 2-02. 10
+55 samples p a r t i a l l y melt
sample i n i t i a l tempera t u r e -170 +25 +55 -170
It i s obvious t h a t t h e IR-spectrum p e c u l a r i t i e a and much weaker e f f e c t of t h e i n i t i a l temperature on t h e polymerization a t s t e p p i n g l o a d i n g a r e governed by t h e v e c t o r i a l n a t u r e of t h e e f f e c t of t h e shock wave upon t h e o r i e n t e d monomer molecules i n the c r y s t a l l a t t i - ce. The e f f e c t becomes s t r o n g e r a t m u l t i p l e shock passing through t h e sample.
So f a r t h e mechanism of t h e shock polymerization process has n o t been revealed y e t . Probably, t h e molecules r e l a t i v e motion i n t h e sample a t t h e i r shock compression plays an important r o l e i n t h e process. The motion r e s u l t s , on t h e one hand, i n t h e r e l e a s e of t h e polymer c h a i n s t r e s s which accumulates during t h e chain growth and i t i s r e s p o n s i b l e f o r t h e monomer molecules deformation, on t h e other. The moleculea deformation a r i s e s due t o t h e s h e a r s t r e s s . The s t r e s s and deformation appear i n time of t h e eubstance compression i n s i d e t h e shock d i s c o n t i n u i t y zone d u r i n g a n extremely s h o r t time
%
-
1130 1200 891 y i e l d
%
0.1 1.2 3.2 5.9 f i r s t
pree- s u r e PI GPa
1.8 1.8 1.8 3.3
- 1 0 ' ~ ~ s [5, 253. Only t h e t r a n s l a t i o n a l degrees of fpeedom a r e e x c i t e d d u r i n g t h i s time. Then t h e energy of t h e t r a n s l a t i o n a l degree8 of freedom t u r n s i n t o t h e i n n e r degreea of freedom. The vib- r a t i o n a l degrees o f freedom c o n t a i n t h e main s h a r e of t h e substance i n n e r energy i n complex molecules. The e x c i t a t i o n times i n v a r i o u s bands o f complex molecules d i f f e r c o n s i d e r a b l y and can exceed t h e
[?I
-
4.40 4.60 3.72 f i n a l
pres- s u r e Pf GPa
4.0
4.0
4.0
7.0
excitation t i m e o f the t r a n s l a t i o n a l degtees of f r e e d o m b y s o m e or- d e r s . The e x p e r i m e n t a l data o b t a i n e d i n the l a b o r a t o r y s h o w that the trioxane p o l y m e r i z a t i o n process i s i n i t i a t e d i n the shock w a v e f m n t i n t i m e of the relaxation of the v i b r a t i o n a l degrees of f r e e d o m (
a1 0 " ~
8 ) .It proceed8 i n the d e f o r m e d crystal l a t t i c e o f the mo- n o m e r i n t i m e of the s h o c k w a v e e f f e c t ( - 1 0 - ~ s ) . During t h i s t i m e s o m e tens and even h u n d r e d s of thousands o f the m o l e c u l e s j o i n t o t h e i n c r e a s i n g chain.
BfEFJBUBCES
[l j BDADUROV, G,A . , BARULOV, I .I,, GOLDBINSKY, V. I. , DREbBIN, A. N. , IGNA-
TOVITCH, T. N. , U K H B I L O V , A, N. , TALROZE, V. L. and YAMPOLSKY, Po A. ,
The D i s c o v e r y N 125 (USSR) on 13.03.1973 w i t h the P r i o r i t y on 23.06.1964.
L21 ADADUROV,G.A., BlrRKaLOV,I.M., GOLDANSKY,V.Io, DREBIIIN,A.N.,IGNA- TOVITCH, T.N., BGEKHAILOV,A.N., TALROZB,V,L. and YAMPOLSKY, PA., D o k l . A k a d . N a u k S S S R a (1965) 851.
131 BABPPRE,L.V., DREMIN,A.N,, PBFSCHIN,S.V. and YAKOVLEV,V.V.,
I
