Modified poly properties

Blends of ABS with polycarbonates have been available for several years (e.g. Bayblend by Bayer and Cycoloy by Borg-Wamer). In many respects these polymers have properties intermediate to the parent plastics materials with heat distortion temperatures up to 130°C. They also show good impact strength, particularly at low temperatures. Self-extinguishing and flame retarding grades have been made available. The materials thus provide possible alternatives to modified poly(phenylene oxides) of the Noryl type described in Chapter 21. (See also sections 16.16 and 20.8.)... 

Takagi, Y., Yasuda, R., Yamaoka, M. and Yamane, T. 2004. Morphologies and mechanical properties of polylactide blends with medium chain length poly(3-hydroxyalkanoate) and chemically modified poly(3-hydroxyalkanoate). Journal of Applied Polymer Science 93 2363-2369. 

Plasticizers are very high-boiling liquids that when mixed with polymers like poly(vinyl chloride) modify the properties of the polymer to produce a material with added flexibility without losing other desirable properties such as strength. They are commonly made by reacting phthahc anhydride with a long-chain alcohol (typically eight carbons). 

Our interest in the synthesis of poly (amino acids) with modified backbones is based on the hypothesis that the replacement of conventional peptide bonds by nonamide linkages within the poIy(amino acid) backbone can significantly alter the physical, chemical, and biological properties of the resulting polymer. Preliminary results (see below) point to the possibility that the backbone modification of poly(amino acids) circumvents many of the limitations of conventional poly(amino acids) as biomaterials. It seems that backbone-modified poly (amino acids) tend to retain the nontoxicity and good biocompatibility often associated with conventional poly (amino acids)... 

This cement also has a low setting exotherm, lower than any other aqueous dental cement (Crisp, Jennings Wilson, 1978), which means that it can be mixed swiftly as there is no need to dissipate heat. This property also gives it an advantage over bone cements based on modified poly(methyl methacrylate) which have high exotherms. 

Before fluorination, the dielectric constant ofpoly(bisbenzocyclobutene) was 2.8, and this value was reduced to 2.1 after plasma treatment. No data were reported in the paper on characterization of structure or properties, except for the dielectric constant of the modified poly(bisbenzocyclobutene). The authors did report that the thermal stability offluorinatedpoly(vinylidenefluoride) was inferior to the original poly(vinylidenefluoride) when treated in a similar way. One of the probable reasons for the low thermal stability is that the NF3 plasma degraded the polymer. According to their results, the thickness of fluorinated poly(bisbenzo-cyclobutene) was reduced by 30%. The same phenomenon was observed for other hydrocarbon polymers subjected to the NF3 plasma process. A remaining question is whether plasma treatment can modify more than a thin surface layer of the cured polymer Additionally, one of the side products generated was hydrogen fluoride, which is a serious drawback to this approach. 

Gaboury, S. R. Urban, M. W. Analysis of Gas-Plasma-Modified Poly(Dimethylsiloxane) Elastomer Surfaces. Attenuated-Total-Reflectance-Fourier Transform Infrared Spectroscopy. In Structure-Property Relations in Polymers Urban, M. W., Graver, C. D., Eds. Advances in Chemistry Series 236 American Chemical Society Washington, DC, 1993 pp 777-790. 

Heteropolycondensation of Bis-silanols, III, with Diacetoxysilanes. Heteropolycondensation of bis-silanols, III, was investigated since this approach appeared to offer a relatively rapid preparative route to a number of various siloxane-modified poly(arylene carbonates) which were required in order to obtain structure-properties correlations for such polymers. 

It was found that the reaction conditions which were optimized for the synthesis of poly(arylene siloxanylenes) (43) could be employed for the synthesis of siloxane-modified poly-(arylene carbonates). 2,4,6-Trimethylpyridine (collidine) was selected as the most suitable of all catalysts investigated (43) for the synthesis of the siloxane modified poly(arylene carbonates). Properties of polymers prepared by this method are given in Table I. In comparision to the phosgene-catalyzed homo-polycondensation of bis-silanols, III, the inherent viscosities... 

At the other end of the temperature spectrum, with high thermal stability of siloxane-modified poly(arylene carbonates) also a desired property, the onset of thermal decomposition (40) for polymers 1-12 was found to be in the range of 385-456°C (as determined from TGA curves obtained by heating polymer samples in nitrogen at a heating rate of 20°C/min.). There does not appear to be any pronounced trend in regard to variation of the thermal stability with structure in polymers 1-12. The small differences in the values of T for these polymers can be due... 

P. Perrin and F. Lafuma Low Hydrophobically Modified Poly (Acryhc Acid) Stabilizing Macroemulsions Relationship Between Copolymer Structure and Emulsions Properties. J. Colloid Interface Sci. 197, 317 (1998). 

Sayed-Sweet Y, Hedstrand DM, Spinder R, Tomaha DA. Hydrophobically modified poly(ami-doamine) (PAMAM) dendrimers their properties at the air-water interface and use as nanoscopic container molecules. J Mater Chem 1997 7 1199-1205. 

Seki and Tirrell [436] studied the pH-dependent complexation of poly(acrylic acid) derivatives with phospholipid vesicle membranes. These authors found that polyfacrylic acid), poly(methacrylic arid) and poly(ethacrylic acid) modify the properties of a phospholipid vesicle membrane. At or below a critical pH the polymers complex with the membrane, resulting in broadening of the melting transition. The value of the critical pH depends on the chemical structure and tacticity of the polymer and increases with polymer hydro-phobicity from approximately 4.6 for poly(acrylic acid) to approximately 8 for poly(ethacrylic acid). Subsequent photophysical and calorimetric experiments [437] and kinetic studies [398] support the hypothesis that these transitions are caused by pH dependent adsorption of hydrophobic polymeric carboxylic acids... 

Poly(vinylcarbazole), of course, is the polymer that is generally utilized in electrophotographic imaging processes such as xerography, but the polymer is not totally satisfactory from a mechanical viewpoint (Section 1.11.2.1.1). Better strength, flexibility, ozone resistance and adhesive properties were said to result by utilizing a modified poly(epichlorohydrin)... 

Liu RCW, Cantin S, PerrotFet al (2006) Effects of polymer architecture and composition on the interfacial properties of temperature-responsive hydrophobically-modified poly(Ar-iso-propylacrylamides). Polym Adv Technol 17 798-803... 

Menzel1811 more recently described the properties and behavior of monolayers prepared from azobenzene-containing poly(L-glutamate)s possessing the structures XIX and XX (n= 2) shown in Scheme 11. These monolayers showed photomechanical effects opposite to those described above for azo-modified poly(L-lysine)s. In fact, they expanded when exposed to UV light (trans—>tis isomerization), and shrank when exposed to visible light (ds— trans isomerization). The expansion was found to be smaller than expected from comparison of the monolayer isotherms obtained from irradiated and nonirradiated solutions. This was attributed to the trans-cis photoconversion of the azo units, which occurs with lower yields in monolayers... 

The decorative laminates described in the previous chapter are made with selected thermosetting resins while resins of this type can be moulded and extruded by methods similar to those outlined in the present and the next chapter the materials employed for these processes predominantly are thermoplastic. Many such plastics can be moulded and extruded under suitable conditions, the most important in terms of quantities used being those that combine properties satisfactory for the purpose with convenience in pro-cessing-especially the polyolefins (polyethylene and polypropylene), poly(vinyl chloride), and styrene polymers and blends. Other plastics with special qualities, such as better resistance to chemical attack, heat, impact, and wear, also are used—including acetals (polyformaldehyde or polyoxymethylene), polyamides, polycarbonates, thermoplastic polyesters like poly(ethylene terephtha-late) and poly(butylene terephthalate), and modified poly(phenylene oxide),... 

Recently, we are also able to perform liquid-liquid extractions of water-soluble dyes from water to organic solvents like toluene using the unimolecular dendritic micelles as extractants. These guest-host properties of the modified poly(propylene imine) dendrimers make use of the basic nature of the interior of the dendrimer. Therefore, it is possible to transfer dyes like Bengal Rose into toluene. Although simple tri-octylamines are capable of transferring these dyes as well, it is evident from the experiments that unimolecular dendritic inverted micelles are much more selective, probably due to the shielding effect of the apolar shell [70]. 

Modification of macromolecular material properties by hydrogen bond formation has been demonstrated at the example of thermoreversible networks Stadler modified poly(butadiene) elastomers with urazole groups to introduce hydrogen-bonded cross-links into the system. In fact, thermoreversible cross-linking appeared due to the urazol-urazole molecular recognition, causing intermolecular cross-links [408,467]. The group of Meijer expanded the approach by the synthesis of two... 

Copolymerization can be employed in a similar fashion to modify the properties of the homopolymer of /7-hydroxybenzoic add (5-6). Poly(/ -hydroxybenzoic acid) is an infusible polymer which can be shaped only by compression sintering. A melt processable variation of this high modulus, thermally stable material can be made, however, by copolymerizing an ester of 5-6 with equimolar quantities of terephthalic acid (5-7) and biphenol (5-8) to produce an aromatic polyester which can be fabricated at temperatures near400 C but still retain many useful properties at 300°C. 

The surface activity of organosilicon polymers with backbones other than siloxane is not very well known. Interest in varying the backbone in organosilicon polymers does not normally stem from a desire to modify surface properties. Usually, the purpose of backbone variation is to increase thermal stability, as for example, with poly(silphenylenesiloxane) and poly-(carboranesiloxane) copolymers. Because thermal stability is often achieved by increasing TgS by using rigid backbones, most backbone variations will have a detrimental effect on polymer surface activity. 

Obeid R, Park JY, Advincula RC, Winnik FM (2009) Temperature-dependent interfacial properties of hydrophobically end-modified poly(2-isopropyl-2-oxazoline)s assemblies at the air/water interface and on solid substrates. J Colloid Interface Sci 340 142-152... 

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