Unsaturated polyester modified

Manfredi, L. B., Rodriguez, E. S., Wladyka-Przybylak, M., and Vazquez, A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres, Polym. Degrad. Stabil. 2006, 91, 255-261. 

In the late 1960s, Nutt developed an unsaturated polyester-modified systemP lt2i] called Estercrete. In the preparation of this system, unsaturated polyester resin dissolved in styrene is mixed with portland cement at a polymer-cement ratio higher than 30%, together with a water-soluble redox catalyst. Table 7.3 ° gives the typical formulations of Estercrete. 

Din Dinakaran, K., Aalagar, M. Preparation and characterization of bismaleimide (AI,AI -bismalei-mido-4,4 -diphenyl methane)-unsaturated polyester modified epoxy intercrosslinked matrices. J. Appl. Polym. Sci. 85 (2002) 2853-2861. 

The thermal stability of composites containing natural fibres may also depend on the nature of the matrix. In the case of composites containing unsaturated polyester or unsaturated polyester modified with acrylic acid reinforced with jute fibres it was shown that the composites with modified polyester matrix were more resistant to temperature than the ones with unmodified polyester matrix. The reason for this enhanced thermal stability was the presence of acrylic acid as modifier [45]. 

Vinyltoluene. Viayltoluene is produced by Dow Chemical Company and is used as a resia modifier ia unsaturated polyester resias. Its manufacture is similar to that of styrene toluene is alkylated with ethylene, and the resulting ethyltoluene is dehydrogenated to yield vinyltoluene. Annual production is ia the range of 18,000—23,000 t/yr requiring 20,000—25,000 t (6-7.5 x 10 gal) of toluene. 

Polymers ndResins. / fZ-Butyl peroxyneopentanoate and other peroxyesters of neopentanoic acid can be used as free-radical initiators for the polymeri2ation of vinyl chloride [75-01-4] (38) or of ethylene [74-85-1]. These peresters have also been used in the preparation of ethylene—vinyl acetate copolymers [24937-78-8] (39), modified polyester granules (40), graft polymers of arninoalkyl acrylates with vinyl chloride resins (41), and copolymers of A/-vinyl-pyrrohdinone [88-12-0] and vinyl acetate [108-05-4] (42). They can also be used as curing agents for unsaturated polyesters (43). 

Modified Bismaleimides. Bismaleknide resins may be further modified and blended with other thermoset resins or reactive diluents to achieve either specific end-use properties or processibiUty. Thermoset resins that can be used for modification are unsaturated polyesters, vinylesters, cyanate esters, and epoxies. 

Maleic anhydride is important as a chemical hecause it polymerizes with other monomers while retaining the double bond, as in unsaturated polyester resins. These resins, which represent the largest end use of maleic anhydride, are employed primarily in fiber-reinforced plastics for the construction, marine, and transportation industries. Maleic anhydride can also modify drying oils such as linseed and sunflower. 

These compds may be modified by monocar-boxy lie acids or poly hydroxy alcohols. This definition includes the polycarbonates (qv), which are a well-defined segment of the general class of polyesters. Unsaturated polyesters, which are produced when any of the reactants contain non-aromatic unsaturation, can be cross-linked or copolymerized with an un-saturated copolymerizable monomer. The formulas and properties of the class polyester are as varied and extensive as the reactants themselves. For specific information on the various sub-classes and sub-sub classes, the following refs should be consulted 9, 10, II, 16a, 17,18,... 

The effect of incorporating p-hydroxybenzoic acid (I) into the structures of various unsaturated polyesters synthesised from polyethylene terephthalate (PET) waste depolymerised by glycolysis at three different diethylene glycol (DEG) ratios with Mn acetate as transesterification catalyst, was studied. Copolyesters of PET modified using various I mole ratios showed excellent mechanical and chemical properties because of their liquid crystalline behaviour. The oligoesters obtained from the twelve modified unsaturated polyesters (MUP) were reacted with I and maleic anhydride, with variation of the I ratio with a view to determining the effect on mechanical... 

Superior Environmental Products, Inc. introduced a product based on liquid poly sulfide containing 40% of a surface-modified scrap tire mbber. The product, ER-IOOR, is a coating that can temporarily contain chemical, oil, and gasoline spills. Rodriguez [97] reported that an unsaturated polyester resin containing silane-treated CGR showed better mechanical properties than that containing untreated CGR. 

Variation of Equivalent Weight. In an attempt to produce more flexible coatings, the UPE A formulation was modified to increase the equivalent weight by substituting succinic anhydride for a portion of the maleic anhydride. These unsaturated polyesters were prepared by the same method as above and the compositions and their properties are summarized in Table II. 

Osaka Organic Chemical will embark on volume production of a low-toxicity acrylic ester monomer with extremely low skin irritation, it is briefly reported. Principal applications are as a diluent monomer for UV and EB coating materials and inks, and as a modifier in unsaturated polyester resins, acrylic resins and PVC. OSAKA ORGANIC CHEMICAL INDUSTRIES CO.LTD. 

Since unsaturated polyesters are condensation polymers with rather low molecular weights, there are three things one can do to modify the properties of the polymer, as follows ... 

Applications. Phthalic anhydride is used largely to make plasticizer for polyvinyl chloride. It is also a feed for alkyd resins and. for unsaturated polyesters that are widely used in construction, rharine, and synthetic marble applications. Other minor applications are dyes, esters, drying oil modifiers and pharmaceutical intermediates. 

STYRENE. Styrene, CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM). styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, rubber-modified impact polystyrene, expandable polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile resins (SAN), styrene-butadiene latex, styrene-butadiene rubber (SBR). and unsaturated polyester resins. See also Acrylonitrile Polymers. 

Again, as in many other fields covered in the book, modified epoxies are the most studied systems (toughened epoxies for adhesive coatings and composites). But also rubber-modified phenolics and low-profile unsaturated polyesters for sheet and bulk molding compounds have been extensively studied. 

Another important application is the introduction of a thermoplastic such as poly(vinyl acetate), PVAc, into an unsaturated polyester resin to improve dimensional stability of the mold part. Keeping in mind (sec. 2.3.2) that an unsaturated polyester is dissolved in styrene, the modifier is the third component and the behavior is described with the help of a ternary-phase diagram (Fig. 8.3, Suspene et al., 1991). 

Other chemistries have been used to prepare preformed reactive modifiers for epoxy and unsaturated polyester resins. Particles are generally composed of... 

DMTA is a very interesting tool for characterizing heterogeneous materials in which domains of distinct Tg values coexist. The most interesting cases involve modified thermosets of different types (see Chapter 8). Examples are the use of rubbers (e.g., liquid polybutadiene and random copolymers), or thermoplastics (e.g., polyethersulphone or polyetherimide in epoxy matrices or poly(vinyl acetate) in unsaturated polyesters), as impact modifier (epoxies), or low-profile additives (polyesters). The modifier-rich phase may be characterized by the presence of a new a peak (Fig. 11.10). But on occasions there may be superposition of peaks and the presence of the modifier cannot be easily detected by these techniques. If part of the added polymer is soluble in the thermoset matrix, its eventual plasticizing effect can be determined from the corresponding matrix Tg depletion, and the... 

The model that best represents the curing kinetics of thermosetting resins such as epoxy and unsaturated polyester, and as reflected in a TTT-diagram, is a diffusion modified Kamal-Sourour reaction model [9, 14, 13]. To model autocatalytic cure kinetics, the model can be applied as... 

Incorporation of modified clays into thermosetting resins, and particularly in epoxy35 or unsaturated polyester resins, in order to improve thermal stability or flame retardancy, has been reported.36 A thermogravimetric study of polyester-clay nanocomposites has shown that addition of nanoclays lowers the decomposition temperature and thermal stability of a standard resin up to 600°C. But, above this temperature, the trend is reversed in a region where a charring residue is formed. Char formation seems not as important as compared with other polymer-clay nanocomposite structures. Nazare et al.37 have studied the combination of APP and ammonium-modified MMT (Cloisite 10A, 15A, 25A, and 30B). The diluent used for polyester resin was methyl methacrylate (MMA). The... 

Polyester A resin formed by the reaction between a dibasic acid and a dihydroxy alcohol, both organic. Modification with multi-functional acids and/or bases and some unsaturated reactants permit crosslinking to thermosetting resins. Polyesters modified with fatty acids are called alkyds. 

On the other heind, the linear unsaturated polyester resins find use in memy commercial applications, such as in producing solventless lacquers, and thermosetting molding compounds. The resin is normally prepcured by the reaction of a saturated diol with a mixture of an unsaturated dibasic acid and a modifying dibasic acid or its corresponding anhydride. It is commonly referred to as... 

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