Polyolefine blends

A route to compatibility involving ionomers has been described recently by Eisenberg and coworkers [250-252]. The use of ionic interactions between different polymer chains to produce new materials has gained tremendous importance. Choudhury et al. [60] reported compatibilization of NR-polyolefin blends with the use of ionomers (S-EPDM). Blending with thermoplastics and elastomers could enhance the properties of MPR. The compatibility of copolyester TPE, TPU, flexible PVC, with MPR in aU proportions, enables one to blend any combination of these plastics with MPR to cost performance balance. Myrick has reported on the effect of blending MPR with various combinations and proportions of these plastics and provided a general guideline for property enhancement [253]. 

Roy Choudhury N., De P.P., and Bhowmick A.K., Thermoplastic elastomeric natural rubber-polyolefin blends. Thermoplastic Elastomers from Rubber Plastic Blend (De S.K. and Bhowmick A.K., eds.), Ellis Horwood, London, 1990, 11. 

Roy Choudhury N. and Bhowmick A.K., Strength of thermoplastic elastomers from rubber-polyolefin blend, J. Mat. Sci., 25, 161, 1990. 

It appears that the main determinant in polyolefin miscibility is the way the chains pack together, a feature that controls the intermolecular interaction between molecules. The solubihty parameter approach is predictive in most cases and can be useful in designing polyolefin blends. 

Examples of Irregular Contribution to Interaction Strength for Polyolefin Blends... 

Incorporation of a perfume into PCL or a PCL-polyolefin blend is reported to be a useful method of retaining the fragrance in soaps and detergent bars (81). 

The increase in scientific production on polymer deformulation is considerably higher than the inflation in scientific papers (3.4% as from 1989). Bourgeois [111] has recently described reverse engineering of polyolefins and polyolefin blends. 

ARA Palmans, M Eglin, A Montali, C Weder, and P Smith, Tensile orientation behavior of alkoxy-substituted BA(phenylethynyl)benzene derivatives in polyolefin blend films, Chem. Mater., 12 472-480, 2000. 

Other uses of blends include controlled rate of fertilizer release(77) based on ethylene/vinyl acetate/carbon monoxide polymers which is U.V. sensitive, polyolefin blends with any biodegradable polymers,(78) and polyolefins blended with metals and autoxidizable substrates. (79) Doane and co-workers(80) at the U.S.D.A. have used grafted starches in many applications, including soil stabilization. 

Patent Number US 6096793 A1 20000801 FOAM COMPRISING POLYOLEFIN BLEND AND METHOD FOR PRODUCING SAME Lee S-T Baker J J Sealed Air Corp. 

Fig. 11.4 Comparison of (a) the POX decomposition rate in dodecane at 180°C with (b) the rate of reduction of the batch mixer torque, that is, reduction of the viscosity of the reacting PP, indicates that the two are identical the POX decomposition is rate controlling and the CR-PP reactions are practically complete after 6-7 POX half-lives. [Reprinted by permission from D. W. Yu, Polyolefin Blends Modified through Peroxide Initiated Reactions, Ph.D Dissertation, Department of Chemical Engineering, Stevens Institute of Technology, Hoboken, NJ, 1991.]...

The use of borane-containing monomers clearly presents an effective and general approach in the functionalisation of polyolefins, which has the following advantages stability of the borane moiety to coordination catalysts, solubility of borane compounds in hydrocarbon solvents (such as hexane and toluene) used as the polymerisation medium, and versatility of borane groups, which can be transformed to a remarkable variety of functionalities as well as to free radicals for graft-form polymerisations. The functionalised polymers are very effective interfacial modifiers in improving the adhesion between polyolefin and substrates and the compatibility in polyolefin blends and composites [518],... 

Xie, R.C. and Qu, BJ. 2001. Synergistic effects of expandable graphite with some halogen-free flame retardants in polyolefin blends. Polymer Degradation and Stability 71(3) 375-380. 

PVC can be blended with numerous other polymers to give it better processability and impact resistance. For the manufacture of food contact materials the following polymerizates and/or polymer mixtures from polymers manufactured from the above mentioned starting materials can be used Chlorinated polyolefins blends of styrene and graft copolymers and mixtures of polystyrene with polymerisate blends butadiene-acrylonitrile-copolymer blends (hard rubber) blends of ethylene and propylene, butylene, vinyl ester, and unsaturated aliphatic acids as well as salts and esters plasticizerfrec blends of methacrylic acid esters and acrylic acid esters with monofunctional saturated alcohols (Ci-C18) as well as blends of the esters of methacrylic acid butadiene and styrene as well as polymer blends of acrylic acid butyl ester and vinylpyrrolidone polyurethane manufactured from 1,6-hexamethylene diisocyanate, 1.4-butandiol and aliphatic polyesters from adipic acid and glycols. 

Silicone Polydimethylsiloxane Works by producing a char surface Polyolefins, polyolefin blends, EVA, polycarbonate, polyurethane Dow Corning, GE Silicones... 

In addition to the polyolefin blends designed for thermoplastic elastomer applications, a great deal of interest also has centered on other kinds of blends of polyolefins as has been reviewed recently (see chapter 21 of Ref. 10 by Plochocki). In a recent paper (84), we showed that blends involving polypropylene-high density polyethylene-low density polyethylene in various proportions and combinations exhibit additivity of tensile strength however, there are serious losses in ductility in some cases such that the blends are less ductile than either pure component. It is interesting to note, however, that these losses in ductility can largely be restored by addition of rather small amounts of an amorphous ethylene-propylene rubber (84). 

This is often conducted to make impact-resistant polyolefin blends. For this purpose, isotactic polypropylene, which is tough but somewhat brittle, is produced on the catalyst pellet in a first reaction step, using highly active stereospecific... 

Growing interest in polymer blends is due to the feasibility of varying properties of the materials within wide limits which may modify tensile strength, impact strength, etc. Numerous papers have appeared in connection with the preparation and mechanical properties of polyolefin blends. However, there appears to be a lack of information regarding oxidative stability of this type of blend. 

There have been recent efforts to predict, or at least rationalize, the x parameters of these and other polyolefin-polyolefin blends. Bates et al. (1992) and Fredrickson et al. (1994) suggest that the x parameter is correlated to a difference in statistical segment length of the polymer molecules, on a volume-normalized basis. The volume normalization is required because the definition of the statistical segment length depends on how the monomer unit... 

Graessley et al, (1994,1995) have proposed an alternative scheme that correlates the x values for polyolefin blends with differences in inferred values of the solubility parameters of the pure components [see Eq. (2-31)]. For the series of polyolefins they studied, values of for the pure components can be assigned in such a way that the x parameters of the mixtures computed from Eq. (2-31) are in reasonable qualitative agreement with measured values. Direct estimates of the (5 s can be obtained from the following formula derived from the van der Waals cohesive energy density (Hildebrand and Scott 1950 Krishnamoorti et al. 1996) ... 

K. W. Foreman and K. F. Freed (1998) Lattice cluster theory of multicomponent polymer systems Chain semiflexibility and speciflc interactions. Advances in Chemical Physics 103, pp. 335-390 K. F. Freed and J. Dudowicz (1998) Lattice cluster theory for pedestrians The incompressible limit and the miscibility of polyolefin blends. Macromolecules 31, pp. 6681-6690 E. Helfand and Y. Tagami (1972) Theory of interface between immiscible polymers. 2. J. Chem. Phys. 56, p. 3592 E. Helfand (1975) Theory of inhomogeneous polymers - fundamentals of Gaussian random-walk model. J. Chem. Phys. 62, pp. 999-1005... 

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