Propylene block-copolymers

Around Izod notch Low-density polyethylene Ethylene-propylene block copolymers Cellulose nitrate and propionate ABS and high-impact polystyrene Bis-phenol A polycarbonate... 

Kabanov, A., et al. 1992. A new class of drug carriers Micelles of poly(oxyethylene)-poly(oxu-propylene) block copolymers as microcontainers for drug targeting from blood in brain. J Control Release 22 141. 

Styrene-butadiene or styrene-(ethylene-co-propylene) block copolymers are common compatibilisers for the commingled recyclate from PCW [27]. Improvement of the mechanical properties of heterogeneous PCR (33% PE+39% PVC+28% PET) or (44% PE+1% PP+28% PET+9% PS+2% PVC+16% other plastics) was performed with EPDM or hydrogenated SBS triblocks [52]. 

A common example of a copolymer is an ethylene-propylene copolymer. Although both monomers would result in semi-crystalline polymers when polymerized individually, the melting temperature disappears in the randomly distributed copolymer with ratios between 35/65 and 65/35, resulting in an elastomeric material, as shown in Fig. 1.19. In fact, EPDM rubbers are continuously gaining acceptance in industry because of their resistance to weathering. On the other hand, the ethylene-propylene block copolymer maintains a melting temperature for all ethylene/propylene ratios, as shown in Fig. 1.20. 

Figure 1.20 Melting temperature for ethylene-propylene block copolymers.

Many attempts have been made to synthesise ethylene/propylene block copolymers, referred to as polyallomers, with isospecific Ziegler-Natta catalysts. However, true block copolymers can hardly be synthesised. This is due to the short life of the growing polymer chains [68,241]. Therefore, only in a few cases, when the copolymers are synthesised by adding two comonomers sequentially and under very specific conditions in order to reduce chain transfer reactions, does unambiguous evidence for true block copolymer formation with isospecific catalysts exist [457]. 

A model series consisting of six ethylene-propylene block copolymers (PP/EPR) has been investigated. While the flowability of their matrix (MFR 45 dgmin x), the rubber content (about 23 wt %) and the amount of C2 in the E/P rubber have been fixed, their intrinsic viscosity (IV) has been varied systematically from 1.7 to 6 dg 1 1 (which corresponds roughly to Mw from 150 to 1000 kg mol x). A detailed description of the non-nucleated materials and their performance has been published elsewhere [168]. 

Poloxamers are relatively non-toxic poly(oxyethylene)-poly(oxy-propylene) block copolymers with the general formula... 

Commercial PP and LLDPE resins were used. Their properties are listed in Table IV. For the first stage of the program PP/LLDPE = 50 50 blends were examined with or without 10 wtX of compatlblllzlng ethylene-propylene block copolymer EP-1 or EP-2 ( 39. Surprisingly, even at -40°C, the mechanical properties of the two-component blends were found to be either additive or synergistic. Addition of EP did not significantly affect them. For this reason, in the more extensive studies which followed only two component LLDPE/PP blends were investigated (40, 41, 69). 

By sequential copolymerization of styrene and propylene using a modified Ziegler-Natta catalyst, MgCl2/TiCl4/NdClc(OR) //Al(iBu)3, which was developed in our laboratory, a styrene-propylene block copolymer is obtained. After fractionation by successive solvent extraction with suitable solvents, the copolymer was subjected to extensive molecular and morphological characterization using 13C-NMR, DSC, DMTA, and TEM. The results indicate that the copolymer is a crystalline diblock copolymer of iPS and iPP (iPS-fo-iPP). The diblock copolymer contains 40% iPS as determined by Fourier transform infrared spectroscopy and elemental analysis. 

Tirpak,G.A. Detection of ethylene homopolymer in ethylene-propylene block copolymers. J. Polymer Sci. A, 2, 705-709 (1964). 

Polystyrene-b-poly (ethylene-co-propylene) block copolymers were also used to compatibilize PP/PS blends (165,166). They showed similar effect to block copolymers of styrene and butadiene. Fig. 2.10 indicates that they locate in the blend interface. 

An attempt has been made (56) to understand the role of the structural factor when MAH was grafted to heterophase PP. The latter was a mixture of highly crystalline homopolypropylene, which made the matrix and copolymers dispersed in the PP matrix similar to rubber particles. During fractionation of the heterophase PP, three fractions were separated PP ( 50 wt%), EPR with irregular distribution of ethylene units ( 43 wt%), and ethylene-propylene block copolymer (EPM) ( 2 wt%). Peroxide initiators were DTBP (di-tert-butyl peroxide), S =... 

QU2 Quintana, J.R., Villacampa, M., and Katime, 1., Micellization of a polystyrene-Z>/oc -poly(ethylene/propylene) block copolymer in ketones, Po/ywier, 34, 2380, 1993. 

Lee, S.-G., Lee, J. H., Choi, K.-Y., and Rhee, J. M., Glass transition behavior of polypropylene/polystyrene/styrene-ethylene-propylene block copolymer blends, Polym. Bull, 40, 765-771 (1998). 

Ethylene-propylene block copolymer PVB and plasticized PVB 30% (wt) mica... 

Polymer (B) ethylene/propylene block copolymer 2000SA2... 

THERMAL PROPERTIES OF ETHYLENE-PROPYLENE BLOCK COPOLYMERS. 

EFFECTS OF IONIZING RADIATION ON THE THERMAL PROPERTIES OF LINEAR HIGH POLYMERS. 5. ETHYLENE-ISOTACTIC PROPYLENE BLOCK COPOLYMER. 

Kraton G 1701] Kraton G 1701X, Kraton G 1702X. See Styrene-ethylene-propylene block copolymer... 

Multi-Flex TPE G 7680 [Multibase http //www.multibase.com], Multi-Flex TPE G 7890 [Multibase http //www.multibase.com], Multi-Flex TPE G 7940 t[Multibase http //www.multibase.com], Multi-Flex TPE RP-6568 B2 [Multibase http //www.multibase.com], Multi-Flex TPE RP-6568 C [Multibase http //www.multibase. com] Styrene-ethylene-propylene block copolymer Uses Thermoplastic elastomer used as a modifier in solv.-based weatherable sealants Trade Name Synonyms Kraton G 1701 t[Kraton Polymers http //www.kraton.com], Kraton G 1701X [Kraton Polymers http //www.kraton.com]-, Kraton G 1702X [Kraton Polymers http //www.kraton.com]... 

Toluene-2,6-diisocyanate sealant modifier, solvent-based weatherable Styrene-ethylene-propylene block copolymer sealant, automotive Toluene bis (dimethyl urea) sealant, canal walls Bentonite sealant, casting... 

Most of the literature covering ethylene-propylene block copolymers are process patents(55,56), however, specific papers on the subject do exist. For example, it has been reported that a block copolymer of 4-methyl pent-l-ene and propylene was prepared using a... 

P-E-P Propylene-ethylene-propylene block copolymer PES Polyethersulfone PEST Polyester(s)... 

To improve the low-temperature impact strength of PP, it was blended with a small amount of HOPE and ethylene-propylene block copolymer, EP... 

Polypropylene/polyethylene, PP/PE, blends were compatibilized by addition of ethylene-propylene block copolymer, EPR. The resulting blends showed improved low-temperature impact strength ... 

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