The purpose of electrical insulation may generally be described as the prevention of unwanted contacts between the electrical conductors at different potentials. A Nicolet Impact 400D FT-IR Spectrophotometer was employed for the measurements. Since many years, unsaturated polyester composites have been used in very varied technology fields as naval constructions, offshore applications, water piping, building construction and automotive applications. The sample for analysis was kept in an oven at 35°C under vacuum overnight. Fennimore and Martin developed this method [98]. However, the use of these materials is limited due to their poor fire performance. Additives in different amount were mixed with prepolymer polyester resin in a round bottom flask equipped with high speed agitator. Due to the proprietary nature of the compositions, the soybean oil based resin will only be referred as XP-07, Unsaturated polyester, any of a group of thermosetting resins produced by dissolving a low-molecular-weight unsaturated polyester in a vinyl monomer and then copolymerizing the two to form a hard, durable plastic material. Thus the results of present study are in good agreement with the reported values. The GPC system was equipped with two ultrastyragel columns packed with styrene-DVB copolymers of 103 and 106 A0 porosity connected in series to cover an exclusion limit of 200 to 10 × 106. TGA thermograms of all the composites indicate a similar decomposition pattern of two steps degradation. Fire Resistance Formulation and LOI [92]. a typical unsaturated polyester resin system with a focus on the thermal, mechanical and impact properties and how they are greatly enhanced over the typical polyester resin system. The styrene acts both as a cross-linking agent and as a viscosity reducer so that the resin can be processed. Antimony trioxide and fly ash gives poor results compared to other fillers and also mechanical performance decreases with increase in amount as antimony trioxide has poor binding property. also be room temperature cured when a reducing agent such as a
Recently, environmental problems relating to brominated flame retardants (BFRs) have become a matter of greater concern than ever before, because of the recent marked increase in levels of polybrominated diphenyl ethers (PBDEs) found in human milk in Sweden and North America [177]. The Department of Occupational Medicine at Aarhus University in Denmark concluded that styrene may cause cancer in humans. Roofing, boat, polywood, putty, button, pultursion, smc, bmc, etc. Modification of unsaturated polyester resin was carried out in three neck flask equipped with stirrer. Rockwell Hardness study was carried out at room temperature according to standard method of testing ASTM D-785 [101]. Raw Kaolin is the common name for the mineral products comprised totally or substantially of the aluminium-silicate clay. The resultant modified unsaturated polyester resin was named as low styrene emission unsaturated polyester resin (LSEUPR). Due to this filler can be easily and uniformly dispersed throughout the polymer matrix and leaching of filler from the polymer matrix is prevented. Mechanical properties of laminates improve remarkably with introduction of acrylic monomers and fillers. Figure 10 Illustrates a typical setup for an arc resistance test. The use of glass-reinforced laminates in the field of dielectric materials has been of prime importance in the engineering materials. Materials Testing. Vinyl ester resins were developed in the late 1950’s and early 1960’s i.e. In 1929, Arvin and Carothers developed unsaturated polyester resins from maleic acid and ethylene glycol reacted at temperature 175 0-185 0 C. Ford Motor Co. Ltd. synthesized unsaturated polyester resin by reacting maleic anhydride and phthalic anhydride with propylene glycol at 100 0 C and then at 250 0 C till the acid number diminished to the value less than 50 (mg of KOH per gm of sample). In every case the current must be sufficiently small to eliminate secondary effects such as temperature rise, mechanical stress and electrochemical action. They have an advantage over a traditional filler antimony oxide to increase the fire retardancy without decreasing mechanical and thermal properties of the composites. The styrene monomer in the unsaturated polyester resin is an environmental and occupational health problem due to evaporation and emissions, which occur during the processing of the resin. Gelcoat and Top Coat are used as surface coating materials for modular baths and washstand countertops as they not only protect the surface of FRP (fiber-reinforced plastic) products but also provide superior finishing. In spite of hydrolytic instability problems of these materials, mainly due to the fact of their pre-polymer ester functions [61-62], interest in unsaturated polyester resin comes from their low cost and easy processing. Increase in strength with increase in filler content is due to the reinforcement action provided by the filler particles to the polymer matrix. monomeric form, which is reacted with the double bond of maleic anhydride via Diels-Alder addition. Polyesters [1-3] are one of the most versatile synthetic copolymers. There are some solutions [63]. ISO/Boat. All products have a wild field of application. The crushed powder sample (2-3mg) in the form of a pellet was prepared by mixing with dry KBr (1g). The development of water is the by-product of this polycondensation process. It has good thermal stability, lower density and good miscibility with most of the polymers. To date our community has made over 100 million downloads. Electrical resistance formulations were prepared by adding various additives viz: raw kaolin, surface treated kaolin and mica in different amounts (10 to 40 wt %) in unsaturated polyester resin (table-3). These resins are compounded with varied fillers, reinforcements and cured by using free radical initiators to yield thermoset articles having a wide range of chemical and mechanical properties depending upon the choice of diacids, diols, cross- linking agents, initiators and other additives [27]. This is because of its high resistance property. It is a solid white powder and is used mainly as fire retardant additive and as pigment. The reported values for asbestos filled melamine are 1.2 x1012. be employed to tie off excess of hydroxyl and carboxyl groups and to reduce the molecular weight of the final prepolymer. Class C fly ash is produced normally from lignite and sub-bituminous coals. Composites prepared using fillers give better fire resistance than unfilled composites and also there is increase in fire resistance with increase in amount of filler. An IR spectrum of prepolymer polyester resin is shown in figure-3. al. PL GEL mixed B type of column, Tetrahydrofuran as solvent and refractive index detector were used in this analysis. plastic articles. In this work, fire behaviour of composites was evaluated. A strong absorption band at 755 cm-1 and a weak band at 1004 cm-1 can be attributed to -C-H bending arising from 1 and 3 position in benzene ring and –C=CH bending arising from isomerisation of maleic anhydride to fumarate during polymerization. The mechanical and fire resistance properties of the cured samples depending on the type of acrylic monomer and amount and type of filler. The results are expressed in terms of kinetic energy consumed by the pendulum in order to break the specimen. Synthesis of bio-based unsaturated polyester resins. methacrylate and allyl ethers as well as by difunctional vinyl
The Rockwell hardness test measures the net increase in depth impression as the load on an indentor is increased from a fixed minor to a major load and then returned to minor load. Unsaturated polyester resin find application in several industries such as marine, oil & gas, transportation, construction, and manufacturing industries. The details about fillers are given as below: The formula of hydroxyapatite is Ca10(PO4)6(OH)2. The market research report identifies and prioritizes opportunities for Global unsaturated Polyester Resin in Automotive Composites by Market application, intermediate material type, country and by region. due to their low shrinkage and low styrene content1 DCPD can be reacted with any dicarboxylic acid
Additives in different amount were mixed with low styrene emission unsaturated polyester resin in a round bottom flask equipped with high speed agitator by means of agitation. The primary function of thermosetting plastics in electrical applications has been that of an insulator. The fire behaviour of composites can also be improved by using a halogenated resin [175] in place of a traditional resin. During esterification reaction, water formed as by product and was continuously removed from the reaction mass as it inhibits the rate of reaction. etc. The volume resistivity and surface resistivity were measured in terms of resistance of composites by a Hewlett Packard Model No. The type of
After 15 second the major load was removed and the specimen was allowed to recover for 15 second. When the temperature was dropped to 800C, 0.5mol Maleic anhydride (MA) was added and continues heating at 150-2000C until an acid number of 20 were reached. Unsaturated polyester resin prepared from isophthalic acid, maleic anhydride and neopentyl glycol was mixed with dicyclopentadiene resin and styrene to give dielectric compound for electric machines [36]. These studies showed clearly that the styrene emission cannot be avoided as long as the basic chemical composition is kept unchanged. Hydroxyapatite and zinc borate gives good results as compared to other fillers. This instrument measures the weight loss as well as the rate of weight loss of a material continuously as a function of increase in temperature. The composites can be used for electrical, electronic and electro technical applications like circuit breakers, switch board cabinets, automotive distributor caps, printed circuit board etc. The anhydrides and acids can also be condensed with epoxy resins
Bharat Dholakiya (September 26th 2012). The test sample is positioned vertically in a glass chimney and an oxygen/nitrogen environment is established with a flow from the bottom of the chimney. peroxide (BPO), and acetylacetone peroxide (AAP). Ford Motor Co. Ltd.[29] synthesized unsaturated polyester resin by reacting maleic anhydride and phthalic anhydride with propylene glycol at 1000C and then at 2500C till the acid number diminished to the value less than 50 (mg of KOH per gm of sample). The use of antimony oxide and fly ash increases the fire resistance behaviour but there is decrease in mechanical properties and thermal stability. 8900 Impact Machine was used for the present study. Mica is also chemically inert and is stable when exposed to electricity, light, moisture and extreme temperatures. Polyester resins are used in sheet moulding compound, bulk … Many other glycols and acids or anhydrides can be used to taylor
The mixture was mechanically stirred and heated at 1200C under nitrogen gas stream. isophthalic acid, maleic anhydride and neopentyl glycol [53] or tetrabromobisphenol-A [51] in place of phthalic anhydride or propylene glycol. A medium absorption band at 1447.76 cm-1 can be attributed to –C-H bending. Prepolymer polyester resin synthesized by above procedure was analyzed by GPC, FTIR and TGA. Alkyds are the reaction products of polyhydric alcohols with fatty acids followed by reaction with dibasic acids. In conventional unsaturated polyesters the styrene content varies between 35- 45wt %. These resins are very reactive and have very short life. Unsaturated polyester resin is widely used as a body filler for roofs, interiors, bumpers, and vehicles to repair damaged parts. It functions as a reactive diluent and as a crosslinking agent. An Interpenetrating polymer network (IPN) consists of two or more
By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers. Acrylic modified unsaturated polyester resin having good cracking resistance, flexibility and thixotropic property were synthesized using 65 parts 0.15:1.0:0.3:0.7 molar ratio of dicyclopentadiene : fumaric acid : ethylene glycol : diethylene glycol copolymer and 35 parts of 2-hydroxy ethylmethacrylate [34]. The composites obtained from fire resistance formulations were characterized by Limiting oxygen index according to ASTM D-2863[91]. His work involved A-B -hydroxy acids, the polymerization of certain lactones and the esterification of A-A linear diols with B-B terminal aliphatic dicarboxylic acids. Composites prepared using fillers give better fire resistance than unfilled composites and also there is increase in fire resistance with increase in amount of filler. Grades with different viscosities, unsaturation and cure speed are
polymers which are at least partially interlaced on a microscopic scale
An IR spectrum of cured polyester resin is shown in figure-9. large number of companies including Ashland, Reichhold, and Royal DSM. temperature. The results clearly indicate that the composites of present study can be used in all fire resistance applications. All the measurements were carried out at room temperature. The resultant formulations were compounded with glass fibre as reinforcing materials and benzoyl peroxide as curing catalyst for composite preparation. Electrical resistance of polyester resins can be further improved by blending with various additives such as antimony trioxide [54], kaolin [55], mica [56] and calcium carbonate [57]. Such a polymer is called copolymer and the process of its synthesis is called copolymerization. Survey of literature revels that there are many reports about the fire resistance behavior of the glass reinforced composites [64-88]. Zwick model No. Similar improvements in flexibility can be achieved with ether glycols such as diethylene
Duroct ® Cobalt 12% NDA: Duranap ® Cobalt 6% In filled composite (figure-6) loss of weight at 100, 200, 300, 400 and 450 OC is -0.96, -10.30, -28.58, -65.00 and -66.02% respectively. Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too. The use of composite materials for building equipment is becoming increasingly important and it has been clearly demonstrated by tests on structures that composite materials with an organic matrix behave well than traditional materials (woods in the naval area, aluminium in the aeronautic sector), in the case of a fire. Composites were prepared by hand lay-up technique using about 50 weight percent of glass fibre and filler. In practice material is often called the self extinguish materials if LOI is greater than 26 [99]. The results clearly indicate that the composites of present study can be used in all electrical applications where PF, MF and UF resins are used. This versatility in the properties of the final thermoset product associated with comparatively low cost has renewed the interest in these resins as an important matrix material for wide range of applications. This work deals with the development of low styrene emission unsaturated polyester resins with improved fire resistance and mechanical properties. Table–2 represents Izod impact strength, Rockwell hardness and Flexural strength. The number average (Mn) of polyester resin sample is 1554, weight average (Mw) is 3576 and polydispersity (Mw/Mn) is 2.301. sytem. They combine the excellent mechanical, chemical and solvent resistance properties of epoxy resins with the properties found in the unsaturated polyester resins. the experiment was carried out a distance between two jaws to be 7.5 cm apart. The band at 1736 cm-1 confirms the presence of –C=O ester group and also confirms the formation of polyester resin. Modification of unsaturated polyesters in this way is a possibility to get unsaturated polyester resins with low styrene emission, better fire resistance and mechanical properties, lower shrinkage, reduced brittleness and increased flexibility. In the present study limiting oxygen index (ASTM D-2863) was determined to characterize the composites. The flame-retardant property, however, is not affected by particle size. Increase in mechanical properties with increase in filler content is due to the reinforcement action provided by the filler particles to the polymer matrix [103-104]. The Xylene was completely distilled out and reaction product was allowed to cool. For thermoset products, the resultant resin was blended with styrene for cross-linking and small amount of peroxide as initiator. After the oligomer was kept at 160 °C for 6 h under the vacuum of 0.09–0.095 MPa, it was cooled to 100 °C and the target resin was obtained. Also cost-effective electrical composites can be formulated with competitive performance by using cheaper and widely available fillers. but do not dissolve in solvents, and creep and flow is strongly suppressed. How? These resins provide enhanced thermooxidative resistance, improved processability and low linear shrinkage
For the measurement, a specimen was cut from the fabricated composite (6.4 x 1.27 cm2) and V notched (2.5 mm) at the middle. These resins were introduced commercially in the 1980s and have gained significant market share
When the temperature was dropped to 800C, 21.24 gm (0.5 mol) Maleic anhydride (MA) was added and continues heating at 200-2250C until an acid number of 25 were reached. The adequacy of the fire resistance performance of these filled composites is dependent on both types of filler and incorporation level of the fillers. This will ultimately improve the performance of composites. The producers of unsaturated polyesters started therefore to search actively for alternatives to styrene and started to develop additives inhibiting styrene emission. Refractive Index detector was used with internal temperature of 350C for peak detection. Hydroxyapatite can be found in nature or synthesized by precipitation method using chemical reagents. DCPD modified resins are produced by Deltech, Polynt, and Dow
There are several types of polyesters which are used, and their properties depend upon the acids and alcohols used in their formation. This compound can be physically blended in polymers to suppress, reduce, delay or modify the propagation of flame through polymeric materials. Where,A = Area of the specimen, cm2, t = Thickness of specimen, cm, Rv = Volume resistance (), For surface resistivity, the electrodes were placed on the same surface of the specimen at a fixed distance and direct voltage was applied between the two electrodes. Literature survey reveals that there are many reports about the synthesis and modification methods of unsaturated polyester resin [41-49]. Electrical Resistance Composite Formulation. Resin Viscosity Application VE Resin Vinylester Epoxybispehnol A vinyl ester ~ 500 mPas Parts of high chemical resistance OAResin 1 UPES ... Unsaturated Polyester Resins & Vinyl Ester Resins Additives from Evonik. Download : Download full-size image; Scheme 1. A Nicolet Impact 400D FT-IR Spectrophotometer was employed for the measurements. Mica is phyllosilicate mineral that have a layered or platy texture. Unsaturated polyester resins are one of the most important matrix resins for commodity glass fibre reinforced composites [171]. Electrical resistant polyester resins can be prepared by using dibasic acids e.g. bonds of the prepolymer but also undergoes homopolymerization. Composites prepared using fillers antimony trioxide, fly ash, zinc borate, hydroxyapatite, mica, surface treated kaolin and raw kaolin gives better performance than unfilled composites and also there is increase in mechanical properties with increase in amount of fillers, but leaching of fillers observed in mica and raw kaolin when amount exceeds more than 30 weight %, while the surface treated kaolin filled composites doesn’t show such problem. 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Various physical properties construction, and Royal DSM is also chemically inert and is used mainly as fire retardant and... Tanks etc companies including Ashland, Reichhold, and puts the academic needs of the materials. Viscosity reducer so that the resin can be prepared by hand lay-up technique about! ( MEKP ), the world 's leading publisher of Open Access especially from IntechOpen! Step can be processed unsaturated polyester resin application London head office or media team here,! To cured conventional polyester resin has good thermal stability is of paramount importance filler can be easily uniformly... Vinyl cure can lead to the reinforcement action provided by the polycondensation reaction between polyacids and polyalcohols LSEUPRC lower... Of peroxide as curing catalyst for composite preparation ( table-6 ) according to product type 2015! Circuit would be negligible structure of vinyl esters are dicyclopentadiene ( DCPD ) modified resins trends in the of. Solid white powder and is used mainly as fire retardant additive and as a reactive diluent and pigment. Was assigned to degradation of resin [ 41-49 ] industry, e.g pozzolanic material and has of.