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Переработка пластмасс

Unaxial tensile strength of polymer fluids

Sabsai O. Yu., Borisenkova E.K., Optov V.A. 

Third Europ. Rheol. Conf., Edinburg, Elsevier Applied Science, London, Cand, New York, 1990.

 
 
  

Abstract

     In dependance of the volume concentration of a filler there are two different rupture mechanisms that are realising for dispersion-filled high polymer melts.

Introduction

     At high deformation rates polymer fluids may loos their ability to flow as long as necessery and can break according to cured rubber long-term durability mechanism. In [1] for the first time the condition of fluid "high polymers" rupture at unixial extention was determined as follows:

/( - *) = cost > 0; > *           (1)

where: - the true break stress, * - the rupture recoverable deformation (Hencky measure), * - the critical recoverable deformation, below which the rupture probability is equal to zero. The rupture of cured high polymers may occur at any value of deformation and thus for them * = 0 [2], but in case of "high polymer melts" rupture * 0 and it does not depend on loading conditions and temperature [1, 3].

Materials and Methods

     On Fig 1-3 there are represented the results of investigation of dispersion-filled "high polymer melts" rupture. In a regime of constant rate of unixial deformation at temperature 293 K series of experiments were carried on the base of 1,2-polybutadien (PB) with MM = 1.8 x 105 and Mw/Mn = 1.3. It contained 84% 1,2-units , its glass temperature was equal to 256 K. As despersed fillers were used shale-ash and radiation-cured up to the glass and then milled 1,2-PB. An average size of particles in both cases was equal to 20 mkm.

Results

     As shown in Fig. 1 the conditions of durability (1) stays the same, but the value * falls linearity with the increase of filler concentration vol and does not depend on type or nature of filler. There is a critical concentration of a filler cr = 25%vol - such, that at > cr  * = 0 (Fig. 2).
     At > cr the filled polymer melts may break at any recoverable deformation, but in such cases the kind of the dependance 
- changeg qualitatively (Fig. 3). As shown in Fig. 3 there are limited maximally achievable rupture stresses and recoverable deformations at unixial  extention for highly-filled polymer melts. 

  
  

 Figure 1. Rupture stress * versus rupture recoverable deformation . 1. - PB; 2. - (PB + 10%vol of shale-ash); 3. - (PB + 15%vol of cured PB); 4. - (PB + 20%vol of shale-ash). 

 

  
  

 Figure 2. Critical recoverable deformation * versus volume concentration of a filler .

  

 
 

Figure 3. Rupture stress * versus rupture recoverable deformation . 1. - PB; 2. - (PB + 25%vol of cured PB); 3. - (PB + 30%vol of shale-ash).

 
 
 

References

1. E.K. Borisenkova, O.Yu. Sabsai, M.K. Kurbanaliev, V.E. Dreval, G.V. Vinogradov, Polymer, 1978, Vol. 19, December, p. 1473.
2. Smith T., in Rheology (ed. F.R. Eirich), Acad. Press, N.-Y., 1969, 5, p. 143.
3. Chalaya N.M., Sabsai O.Yu, Abramov V.V. Progressing of filled composit materials, Moscow, NPO Plastic, 1982, p. 80.