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Polypropylene-block-poly

Similar results were found when a polypropylene-block-poly(propylene glycol), PP-b-PPG, diblock copolymer was utilized as compatibilizer its ability to increase the interlayer distance of PP/dimethyl dioctadecyl ammonium-modified montmorilonite hybrids was studied and compared with the corresponding behavior of PP-g-MA [55]. The ratio of compatibilizer to organoclay used was low but nevertheless 2 wt% of PP-b-PPG resulted in a 4A increase of interlayer distance, which was better than what was observed utilizing maleated PP under the same conditions. [Pg.386]

Fukui, Y. and Murata, M. (2002) Living polymerizations of propylene and syntheses of atactic polypropylene-block-poly(ethylene-co-propylene) using metallocene catalyst systems. Applied Catalysis, A General, 237,1-10. [Pg.307]

Radulescu, A., Mathers, R.T., Coates, G.W. etal. (2004) A SANS study of the self-assembly in solution of syndiotactic polypropylene homopolymeis, syndiotactic polypropylene-block-poly(ethylene-co-propylene) diblock copolymers, and an alternating atactic-isotactic multisegment polypropylene. Macromolecules, 37,6962 971. [Pg.312]

The concept of PO macroinitiators centers on the introduction of an initiation moiety into an olefinic polymer chain for polymerization. The most effective route for preparing PO macroinitiators is by employing functional polyolefins containing hydroxyl groups or other reactive groups. These functional POs are prepared by copolymerization of olefins with functional monomers and post-polymerization reaction, as mentioned above. In the case where an initiation moiety was at the chain-end of the polyolefins, a block type copolymer is produced. It has been reported that thiol-terminated PP was used as polymeric chain transfer agent in styrene and styrene/acrylonitrile polymerization to form polypropylene-b/odc-polystyrene (PP-b-PS) and polypropylene-btock-poly(styrene-co-acrylonitrile) (PP-b-SAN) block copolymer [19]. On the other hand, polymer hybrids with block and graft structures can be produced if initiation moieties are in the polymer chain. [Pg.84]

Block copolymers can be produced from terminally borane-containing polyolefins. These borane-containing POs can be synthesized by the metallocene-catalyzed (co)polymerization of olefin(s) monomer with 9-BBN as a chain transfer agent or by the metallocene catalyzed copolymerization of olefins with allyl-9-BBN [55,56], as referred to above. Alternatively, borane-containing POs were prepared by hydroboration of terminally unsaturated PO, for instance, terminally vinyl PE and terminally vinylidene PP [33-35,57]. Such method could produce diblock copolymers, such as polyethylene-block-poly(methyl methacrylate) (PE-fo-PMMA), polypropylene-foZock-poly(methyl methacrylate) (PP-fc-PMMA), polypropylene-foZock-poly(butyl methacrylate) (PP-fc-PBMA), and PP-fc-PS. [Pg.93]

Pluronics tri-block copolymer polyethylene oxide-polypropylene oxide-poly-ethylene oxide (PEO-PPO-PEO)... [Pg.483]

AA acrylic acid LDPE low density polyethylene NBR poly (butadiene-acrylonitrile) PA polyamide PAA poly(acrylic acid) PAN polyacrylonitrile PB polybutadiene PC polycarbonate PDMS polydimetylsiloxane PE polyester PEBA polyetheramide-block-polymer PI polyimide PMA poly(methyl acrylate) POUA poly(oxyethylene urethane acrylate) PP polypropylene PPO poly(phenylene oxide) PTMSP poly(trimethylsilylpropyne) PUR polyurethane PVA poly(vinyl alcohol) PVC poly(vinyl chloride). [Pg.98]

Self-assembled block copolymers are basically amphilic molecules which contain distinctively different polymers. This block copolymer contains two or more polymers quantitatively in the form of blocks. Some of the block copolymers are polyacrylic acid, polymethylacrylate, polystyrene polyethylene oxide, polybutadiene, polybutylene oxide, poly-2-methyloxazoline, polydimethyl sUoxane, poly-e-caprolactone, polypropylene sulfide, poly-A -isopropylacrylamide, poly-2-vinylpyridine, poly-2-diethylamino ethyl methacrylate, poly-2-(diisopropylamino) ethyl methacrylate, poly-2-(methacryloyloxy) ethyl phosphorylcholine, and polylactic acid. These copolymers contain more than polymers to form certain configurations like linear, branched, patterned. For example, if we take three polymers named A, B, and C, they can be combined to form arrangements AB, BA, AA, BAB, ABCAB, ABCABC, ABABAB, etc. in the form of branched configuration it forms (ABQa, (ABA)a, (AB)4, etc. Depending on the above-mentioned number of blocks, they are named as AB diblock copolymers, ABC triblock copolymers, ABC star block copolymers, etc. The covalent linkage between these different blocks of polymers makes macroscopic phase separation impossible, that is, in its place the phase separation... [Pg.40]

POM Polyoxymethylene PPBC Polypropylene block copolymer PPHP Polypropylene homopolymer PPS Polyphenylene sulphide PPO Polyphenylene oxide PS Poly styrene... [Pg.1177]

Figure 8. Comparison of the coefficients of friction (jr) values for the sliding of the thermoplastics, polypropylene (PP), polyamide-6,6 (PA-6,6) and polyethylene (PE), against a stainless steel substrate lubricated by the aqueous lubricants containing sodium dodecylsulphate, poly(ethylene o ide)-block-poly(propylene oxide)-bZock-poly(ethylene oxide) and poly(L-lysine)-grq -poly(ethylene glycol) (PLL-g-PEG). The results for both thermoplastic/stainless steel and stainless steel/thermoplastic (pin/disk) pairs are shown (load, ION diameter of the pin, 6mm sliding speed, 5.1mms number of rotations, 1000). Figure 8. Comparison of the coefficients of friction (jr) values for the sliding of the thermoplastics, polypropylene (PP), polyamide-6,6 (PA-6,6) and polyethylene (PE), against a stainless steel substrate lubricated by the aqueous lubricants containing sodium dodecylsulphate, poly(ethylene o ide)-block-poly(propylene oxide)-bZock-poly(ethylene oxide) and poly(L-lysine)-grq -poly(ethylene glycol) (PLL-g-PEG). The results for both thermoplastic/stainless steel and stainless steel/thermoplastic (pin/disk) pairs are shown (load, ION diameter of the pin, 6mm sliding speed, 5.1mms number of rotations, 1000).
Bar et al. [71] characterized the morphology of blends of poly(styrene)-WocA -poly(ethene-co-but-l-ene)-WocA -poly(styrene) with isotactic and atactic polypropylene block copolymers by ICAFM. Samples deposited from solution onto a glass substrate, dried, and annealed or quenched from the melt and by samples cut by an ultramicrotome were compared with earher TEM results. The polymer film on the side of the film-glass interface was studied rather than the free surfaces of the polymer. [Pg.141]

Bar G, Thomann Y. Characterization of the morphologies and nanostructures of blends of poly(styrene)-block-poly(ethene-co-but-l-ene)-block-poly(styrene) with isotactic and atactic polypropylenes by tappingmode atomic force microscopy. Langmuir 1998 14 1219-26. [Pg.38]

Similarly, the random introduction by copolymerization of stericaHy incompatible repeating unit B into chains of crystalline A reduces the crystalline melting point and degree of crystallinity. If is reduced to T, crystals cannot form. Isotactic polypropylene and linear polyethylene homopolymers are each highly crystalline plastics. However, a random 65% ethylene—35% propylene copolymer of the two, poly(ethylene- (9-prop5lene) is a completely amorphous ethylene—propylene mbber (EPR). On the other hand, block copolymers of the two, poly(ethylene- -prop5iene) of the same overall composition, are highly crystalline. X-ray studies of these materials reveal both the polyethylene lattice and the isotactic polypropylene lattice, as the different blocks crystallize in thek own lattices. [Pg.434]

The living nature of ethylene oxide polymerization was anticipated by Flory 3) who conceived its potential for preparation of polymers of uniform size. Unfortunately, this reaction was performed in those days in the presence of alcohols needed for solubilization of the initiators, and their presence led to proton-transfer that deprives this process of its living character. These shortcomings of oxirane polymerization were eliminated later when new soluble initiating systems were discovered. For example, a catalytic system developed by Inoue 4), allowed him to produce truly living poly-oxiranes of narrow molecular weight distribution and to prepare di- and tri-block polymers composed of uniform polyoxirane blocks (e.g. of polyethylene oxide and polypropylene oxide). [Pg.89]

PESA can be blended with various thermoplastics to alter or enhance their basic characteristics. Depending on the nature of thermoplastic, whether it is compatible with the polyamide block or with the soft ether or ester segments, the product is hard, nontacky or sticky, soft, and flexible. A small amount of PESA can be blended to engineering thermoplastics, e.g., polyethylene terepthalate (PET), polybutylene terepthalate (PBT), polypropylene oxide (PPO), polyphenylene sulfide (PPS), or poly-ether amide (PEI) for impact modification of the thermoplastic, whereas small amount of thermoplastic, e.g., nylon or PBT, can increase the hardness and flex modulus of PESA or PEE A [247]. [Pg.149]

Hot melt adhesives based on poly(3HB-co-3HV) have also been described [119]. Hot melts are commonly used in bookbinding, bag ending and case and carton sealing and are mostly based on synthetic materials such as polyethylene, polypropylene ethylene-vinyl acetate and styrene block copolymers [119]. Hot melts based on PHAs alleviate the dependence on petroleum based materials and allow the development of biodegradable alternatives based on natural raw materials. [Pg.273]

The triblock terpolymer polypropylene oxide)-h-poly[2-(dimethylami-no)ethyl methacrylate]-b-poly[oligo(ethylene glycol) methacrylate], PPO-fc-PDMAEMA-fc-POEGMA, was prepared using the PPO macroinitiator followed by the addition of CuCl, HMTETA, and DMAEMA for the polymerization of the second block and finally OEGMA for the synthesis of the final product (Scheme 54) [128]. [Pg.70]


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See also in sourсe #XX -- [ Pg.84 ]




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