Polypropylene carbonate

Li and co-workers [11] studied the thermal decomposition of polypropylene carbonate at various pyrolysis temperatures by the combination of Py-GC-MS and TGA-IR spectrometry techniques. They discuss the effects of chemical structure, molecular weight, temperature and catalyst on the degradation behaviour. 

Xoller and co-workers [8], and Li and co-workers [9] used Py-GC-MS techniques and thermogravimetric analysis - infrared (TGA-IR) spectroscopy to study the thermal decomposition characteristics of polypropylene carbonate. 

It has been suggested that the thermal degradation of polypropylene carbonate takes place in two steps the scission reaction of the backbone, followed by an unzipping reaction [10]. Finally, carbon dioxide and propylene oxide were produced. The thermal 

Jia and co-workers [11] characterised a solid phase graft copolymer of polypropylene with styrene and maleic anhydride. The graft copolymer was evaluated by Fourier-transform infrared spectroscopy (FT-IR) [12] and Py-GG-MS. 

Kiji and co-workers [13, 14] studied the composition of alternating olefin-carbon monoxide copolymers and their derivatives such as an alternating ethylene carbon monoxide or ethylene-styrene or norborenes, and their modified polymers with primary amines, or using Py-GC-MS. 

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The first report of the copolymerization of an epoxide, namely, ethylene oxide and C02 is contained in a patent by Stevens [6]. However, this process, when carried out in the presence of polyhydric phenols, provided polymers which were viscous liquids or waxes possessing copious polyether linkages with only a few incorporated C02 units. The earliest metal-catalyzed copolymerization of epoxides and C02 was reported in 1969 by Inoue and coworkers, who employed a heterogeneous catalyst system derived from a 1 1 mixture of diethylzinc and H20 [7, 8], Subsequently, Kuran and coworkers investigated a group of related catalysts prepared from diethylzinc and di- and triprotic sources such as pyrogallol, with a slight improvement over Inoue s system for the production of polypropylene carbonate) from PO and C02 [9],... 

Propylene oxide represents a very attractive epoxide monomer for copolymerization with C02, as polypropylene carbonate) is industrially valuable. The low glass transition temperature (Tg) of 313 K, the sharp and clean decomposition above 473 K, and biodegradability of this copolymer are the reasons for its attracting interest in several applications. On a similar basis, H NMR spectroscopy is useful for assessing the coupling products resulting from the reaction of PO and C02 (Figure 8.21). 

Figure 8.22 l3C NMR spectrum in CDCl3 of regio-irregular polypropylene carbonate) obtained from the reaction between propylene oxide and C02. 

Polyesters make tough and wear-resistant urethanes. The one major drawback is the hydrolysis at the ester grouping. The hydrolysis can either be acid or alkali promoted. In more neutral conditions, the major breakdown product is normally adipic acid that catalyses further attack. The normal approach is to use carbodiimides to block further breakdown. Polyols made using polypropylene carbonate produce polyurethanes with polyester characteristics but with enhanced hydrolysis resistance. 

Kuran, W., Polypropylene Carbonate) , in The Polymeric Materials Encyclopedia, CRC Press, Boca Raton, 1996, Yol. 9, pp. 6623-6630. 

Catalysts derived from reaction systems such as triethylaluminium-water and triethylaluminium-water-acetylacetone [225], triethylaluminium-triphe-nylphosphine [226], triethylaluminium-pyrogallol [209] and rare-earth metal phosphonate- triisobutylaluminium-glycerol [227] appeared to be effective in the copolymerisation of propylene oxide and carbon dioxide, yielding high molecular weight polypropylene ether-carbonate)s (Table 9.4) but not the respective alternating copolymer which is polypropylene carbonate). 

The formation of a cyclic carbonate, e.g. propylene carbonate, accompanying the copolymerisation has been explained in terms of the backbiting reaction involving zinc alcoholate species [206,207], This has been confirmed recently [147] by degrading polypropylene carbonate) by using catalysts with zinc phenolate species. The degraded copolymer thus obtained was terminated in its chains with zinc alcoholate species and phenylcarbonate groups. The course... 

On the other hand, polypropylene carbonate) degradation rim in the presence of catalysts containing zinc alcoholate species resulted in the formation of degraded copolymer chains terminated with zinc carbonate species [scheme (31)] [147] ... 

Explain why carbon dioxide can form with propylene oxide in the presence of coordination catalysts a linear polymer, polypropylene carbonate), but with anionic initiators gives only a cyclic carbonate, propylene carbonate. 

Kashiwagi, T., Grulke, E., Hilding, J., Groth, K., Harris, R., Butler, K., Shields, J., Kharchenko, S., and Douglas, J. Thermal and flammability properties of polypropylene/carbon nanotube nanocomposites, Polymer (2004), 45, 4227 1239. 

Attempts to add fillers to polymer blends produced interesting results. Carbon black was added to a polymer blend containing polycarbonate and polypropylene. Carbon black is known to act as a nucleating agent in polypropylene, however, no increase in the temperature of crystallization was observed. Morphological studies showed that carbon black was preferentially located in the polycarbonate phase therefore it did not affect the nucleation of polypropylene. 

The activation energy for the reaction calculated using Kissinger equation was 52.9kJmol and the order of reaction (n) was 0.92. The peculiarity of this system is that two reactions, namely, the reaction between epoxy resin and polypropylene carbonate or epoxy resin and MTHPA shown in Scheme 21.1a and b, respectively, could occur. 

The relaxations corresponding to the glass transition of polypropylene carbonate and epoxy resin were observed in the spectrum (Table 21.9). The glass-transition peak of epoxy broadened as the polypropylene carbonate content increased. An interesting feature of this system was the decrease in the glass transition of epoxy without any change in the polypropylene carbonate peaks. The shift in the epoxy peak was due to the reaction between polypropylene carbonate and epoxy resin. 

The storage modulus for the cured resins with different polypropylene carbonate contents (Fig. 21.20) did not change over the temperature range lower than their a-relaxation, compared with the parent epoxy resin. This implied that the epoxy matrix was toughened by the addition of PPC at no expense of its modulus but with a sacrifice to its thermal properties. The molecular weight of polypropylene carbonate... 

Kozlov, G. V Zhirikova, Z. M Aloev V. Z. Zaikov, G. E. TTie liactal model of nanocomposites polypropylene/carbon nanotubes melt viscosity. In book Nanostructured Rolymers and Nanochemistry Research Rrogress. Ed. Haghi, K. Kubica, S. Zaikov, G. Torun, REKROL, 2012,44-51. 

Zhirikova, Z. M. Kozlov, G. V Aloev, V. Z. TTie fractal model of melt viscosity of nanocomposites polypropylene-carbon nanotubes. Thermophysics of High Temperatures, 2012, 50(6), 785-788. 

Polypropylene carbon dioxide and n-pentane carbon dioxide and n-pentane propane and 1-bntanol propane and ethanol propane and 1-propanol 1998K12 1999MAR 1997WH2 1997WH2 1997WH2... 

T. Kashiwagi, E. Gmike, J. Hilding, K. Groth, R. Harris, K. Butler, J. Shields, S. Kharchenko, J. Douglas, Thermal and flammability properties of polypropylene/carbon nanotube nanocomposites. Polymer 45, 4227-4239 (2004)... 

Maria Omastova and Ivan Chodak prepared conductive polypropylene/ polypyrrole composites using the method of chemically initiated oxidative modification of polypropylene particles in suspension by pyrrole. In order to prepare the composite, polypropylene particles were dispersed in water-methanol mixture and FeCb was added to be used for chemical oxidation. Addition of pyrrole started formation of polypyrrole particles in polypropylene suspension. The electrical and rheological properties of the composite were compared with polypropylene/polypyrrole composite prepared by melt mixing of pure polypropylene with chemically synthesized polypyrrole and with polypropylene/carbon black composites also prepared by melt mixing. Elemental analysis verified presence of polypyrrole in polypropylene matrix. The conductivity studies show that even a very small PPy amount present in composites results in a significant increase in... 

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