Characterization of Acetylene-Terminated Resin Cure States (original) (raw)
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2017
3,496,250 2/1970 Czerwinski ......r 525/65 3,855,176 12/1974 Skidmore ........................ 52.5/113 X 3,894,113 7/1985 Pagel ............................... 52.5/113 X 3,926,904 12/1975 Scola ............................... 52.5/113 X 4,082,895 4/1978 Backderf et al. ..................... 525/65 4,500,660 2/1985 Minamisawa et al. .............. 523/428 4,517,038 5/1985 Miller .................................... 156/98 4,524,181 6/1985 Adam et al. ........................ 52.5/107 4,680,076 7/1987 Bart .................................. 156/306.9
"To study the curing effects on modified urea formaldehyde resins"
Amino resins are an important class of cross-linkers for industrial coatings. Amino resins are formed when amine or amide such as urea or melamine reacts with an aldehyde and is known as Urea formaldehyde resins. It is modified with butanol, makes butylated urea formaldehyde resins (BUFR). BUFR can cure with different resins such as alkyd resins, epoxy resins etc. Curing is the cross linking or hardening of material with catalysts. In this process, we have made a resin material hard by adding the curing agents and in presence of energy. There are number of applications of the curing (i.e. fast coating, in making the composite material, etc.). There are mainly three parameters which affecting the rate of curing, temperature, concentration of curing agent and the thickness of layer. We have been studied the curing effects on BUF resins with curing agent PTSA (p-Toluene Sulphonic Acid). The curing is done by the thermal curing procedure. There are mainly five experiments are performed for different B/U mole ratios. All are modify with alkyd resins. The concentration of curing agent varies by 5%, 10% and 15% and the thickness of the coating layer varies by 100 microns and 200 microns. The temperature varies from 40 to 80 0 C. It has been studied that three parameters vary and make the changes into the rate of curing. Experimental results show, when Butanol to Urea B/U mole ratio gives higher rate of curing. We also studied that, by increasing the concentration of curing agent increases the rate of curing. The thickness of layer of 100 microns will give higher rate of curing as compare to the 200 microns. It means less the thickness of the coating give the higher rate of curing. The XRD analysis has been done here for the modified resins. It gives the information about the interpeak spacing between the molecules and by which the bonding stability can be understand. If the interpeak spacing between the molecules will be high, the curing will not fulfill. If interpeak spacing will be high, the layer will not cure properly.
Cure mechanisms in materials for use in esthetic dentistry
Journal of Investigative and Clinical Dentistry, 2012
The current paper reviews the curing mechanisms found in resin-based materials used in dentistry. Historical aspects of dental products and the associated curing mechanisms are reviewed. In comparison with common industrial procedures, curing methods employed for dental materials are relatively limited because of the need to polymerize quickly in the oral cavity at an ambient temperature. Heat-cure and self-cure dental resins utilize benzoyl peroxide initiator alone with a tertiary amine co-initiator. At present, most dental restorative composites use a camphorquinone-amine complex initiation, visible light-cure, one-component systems, although alternative photoinitiators have been researched and developed. A multiple curing mode in a dual-cure material is a complex combination of various initiation systems. The use of aryl sulfinic acid sodium salt to overcome adverse chemical interactions between simplified adhesives and self-or dual-cure composites is based on another self-cure polymerization mechanism, sulfinic acid-initiated polymerization, proposed by Hagger in 1948. The sodium salt of aryl sulfinic acid reacts with an acidic monomer in simplified adhesives, and is believed to produce radicals. Clinically, it is important to try to optimize the degree of conversion of resin-based materials using proper manipulation and adequate light-curing techniques to ensure the best outcome for materials used to restore teeth.
A polyacetal injection-moulded resin is being marketed for the construction of retentive and supportive components of removable partial dentures (RPDs). Specimens of poly(oxymethylene) cast by commercial laboratories were tested to examine the following physical characteristics: the modulus of elasticity in compression, extension and flexure, stress relaxation, the force displacement behaviour of clasp forms, impact strength and glass transition temperature. Results showed that the material has a flexural modulus lower than that of poly (methylmethacrylate) and is insufficiently rigid to be used as a supporting element for partial dentures. Resin clasps may be resilient enough to engage undercuts for the retention of RPDs but the low flexural modulus requires that the resin be used in greater cross-sectional area than metal alloys in order to gain useful retention. This greater bulk has implications for plaque accumulation and maintenance of periodontal health.
Patent Bioactive Resin-Based Restorative Materials
Claims 1. Use of: i) a composition comprising Portland cement and phyllosilicate; and/or ii) a modified hexacalcium aluminate trisulfate hydrate product formed by the hydration of a composition comprising Portland cement and phyllosilicate, as an additive in a dental adhesive.
Cure monitoring of catalysed cyanate ester resins
Polymer International, 2000
The cure behaviour of two bisphenol A-based cyanate ester resins, AroCy B10 and B30, catalysed by copper acetylacetonate and nonylphenol was studied. For this purpose, differential scanning calorimetric (DSC) and rheological measurements were carried out at temperatures between 130 and 170°C. The cyanate conversion pro®les are ®tted with a second-order rate law in the kinetically controlled regime where a good time±temperature superposition is attained. However, it is necessary to add an empirical kinetic term to give a good description of the entire range of curing. Simultaneously, times to gelation and vitri®cation have been determined by dynamic rheological measurements over the same temperature range. The corresponding conversions have been calculated by correlation of rheological and DSC data, the vitri®cation conversion being slightly higher for the prepolymer. Independent of the cure temperature, a good correlation between cyanate conversion and glass transition temperature was obtained. The isothermal time±temperature±transformation diagrams for these systems are constructed from the kinetic model and the DiBenedetto equation, and show good agreement with the experimental data.