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  • 1
    Electronic Resource
    Electronic Resource
    Thermal analysis of thermoplastic matrices for advanced composite materials: poly(phenylene sulphide)
    Amsterdam : Elsevier
    Thermochimica Acta 199 (1992), S. 133-146 
    Details
    ISSN: 0040-6031
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0040-6031(92)80257-W
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  • 2
    Electronic Resource
    Electronic Resource
    A new kinetic model for polymer crystallization derived by calorimetric analysis
    Amsterdam : Elsevier
    Thermochimica Acta 227 (1993), S. 83-95 
    Details
    ISSN: 0040-6031
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0040-6031(93)80252-6
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  • 3
    Electronic Resource
    Electronic Resource
    Cure behaviour of visible light activated dental composites (1995)
    Springer
    Journal of materials science 6 (1995), S. 155-160 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: During curing of multifunctional methacrylate-based composites for dental restorations, strong structural changes, significantly affecting the final properties of the materials, are observed. In fact, the polymerization of thermoset matrices involves the transformation of a viscous liquid in a glassy network. The final glass transition temperature of the composite matrix may be considered a relevant parameter for the durability of a restoration. In this study, the complex cure behaviour of a commercial dental composite, activated by visible-light, is analysed by differential scanning calorimetry (DSC). The maximum degree of reaction of the crosslinked resin and the characteristic glass transition temperature are quantitatively related to the cure temperature. Furthermore, a kinetic model, accounting also for the diffusion control effects associated with vitrification, is presented. Finally, the cure behaviour expected during practical application of these materials in the oral cavity for dental restorations, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120292
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  • 4
    Electronic Resource
    Electronic Resource
    Cure behaviour of visible light activated dental composites (1995)
    Springer
    Journal of materials science 6 (1995), S. 161-166 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: In this paper, the non-isothermal cure behaviour of a dental composite, activated by visible light, is described using a heat transfer model that, coupled with a reaction kinetic expression, is able to predict the temperature and the degree of reaction in the composite. The temperature and the degree of reaction profiles inside the composite are calculated, as a function of the cure time, taking into account the system geometry, the thermal diffusivity of the composite, and the resin reaction rate. Material properties, boundary and initial conditions and the kinetic behaviour are the input data of the heat transfer model. Once the degree of reaction is known, the glass transition temperature profiles across the thickness of the composite are calculated. Experimentally measured glass transition temperatures are used for the evaluation of an extinction coefficient capable of accounting for the effects of the light absorption through the thickness on the polymerization kinetics. Finally, the effects of the non-isothermal cure conditions on the application of these materials in dental restorations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120293
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  • 5
    Electronic Resource
    Electronic Resource
    In-situ polymerization behaviour of bone cements (1997)
    Springer
    Journal of materials science 8 (1997), S. 75-83 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The polymerization behaviour of bone cements during total hipreplacements is characterized by a fast and highly non-isothermal bulk reaction.In the first part of this paper the reaction kinetics are analysed bycalorimetric analysis in order to determine the rates of polymerization inisothermal and non-isothermal conditions. A phenomenological kinetic model,accounting for the effects of autoacceleration and vitrification, is presented.This model, integrated with an energy balance, is capable of predicting thetemperature across the prosthesis, the cement and the bone and the degree ofreaction in the cement, during in situ polymerization. The temperatureand the degree of reaction profiles are calculated, as a function of the settingtime, taking into account the system geometry, the thermal diffusivity of bone,prosthesis and cement, and the heat rate generated by the reaction according tothe kinetic model. Material properties, boundary and initial cond!itions are the input data of the heat transfer model. Kinetic and heat transfermodels are coupled and a numerical solution method is used. The model is appliedin order to study the effects of different application procedures on temperatureand degree of reaction profiles across the bone–cement–prosthesissystem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018502731892
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  • 6
    Electronic Resource
    Electronic Resource
    A macrokinetic approach to crystallization modelling of semicrystalline thermoplastic matrices for advanced composites (1993)
    Springer
    Journal of materials science 28 (1993), S. 4994-5001 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A theoretical macrokinetic model for the crystallization of polyphenylene sulphide (PPS) matrix for high performance composites is presented. The model, accounting for the induction time due to nucleation, is able to predict crystallization changes in isothermal and non-isothermal conditions, including cold and melt crystallization, and quenching effects. Moreover, a simple expression is proposed for the temperature dependence of the kinetic constant allowing a straightforward calculation of model parameters. Theoretical results are in good agreement with calorimetric experimental data obtained in a wide range of thermal conditions. Time temperature transformation plots, constructed from the model developed for isothermal (TTT) and non-isothermal (CCT) conditions, are presented providing a fundamental tool for understanding the crystallization behaviour of semicrystalline matrices and to determine the most appropriate processing conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00361167
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  • 7
    Electronic Resource
    Electronic Resource
    Study of the Crystallization of an Aromatic Poly-ether-ketone (PK99) by Calorimetric and X-ray Analysis (2000)
    Springer
    Journal of thermal analysis and calorimetry 61 (2000), S. 565-578 
    Details
    ISSN: 1572-8943
    Keywords: crystallization ; DSC ; PK99 ; rigid amorphous fraction ; WAXD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An analysis of the crystallization behaviour of a new poly(aryl-ether-ether-ketone-ketone), PK99, by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) is presented. Isothermal crystallization TG were obtained in the whole range between the glass transition temperature (T g) and the melting temperature (T m) as a consequence of the slow crystallization kinetics stemming from the closeness of these transitions. The calorimetric results, compared with WAXD data, were applied to determine the theoretical melting temperature and crystallization enthalpy. The DSC and WAXD data were combined in order to calculate the total amount of the crystallizable fraction of the polymer, and a model was proposed to explain the difference between the fractions of crystallinity observed with these techniques. The thermal and X-ray data were also correlated with different lamellar morphologies arising from the crystallization conditions. Finally, DSC experiments on the crystallized sample were used to detect the presence of a rigid amorphous phase which does not relax at T g.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010185905642
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  • 8
    Electronic Resource
    Electronic Resource
    Polymerization kinetics of acrylic bone cements by differential scanning calorimetry (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 35-49 
    Details
    ISSN: 1572-8943
    Keywords: bone cement ; DSC ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Bone cements are widely used for the fixation of metallic prostheses in orthopaedics and to form replacements for skull defects in neurosurgery. Acrylic bone cements are based on a mixture of methyl methacrylate (MMA) and a fine powder of polymethyl methacrylate (PMMA). The polymerization of the bone cement occurs in contact with the bone and the prosthesis which act as the boundaries of a bulk polymerization reactor. The kinetic behaviour of the bone cement plays a fundamental role for the final performance of the implant. In this paper, the isothermal and non-isothermal polymerization behaviour of a commercial bone cement is described. A simple phenomenological model, accounting for the autoacceleration ffect, for a diffusion controlled termination mechanism and for the reaction between inhibitor and initiator, is proposed. The reaction kinetics is analysed by DSC. DSC data are used for the determination of the rates of polymerization under isothermal and non-isothermal conditions. The experimental data are processed to calculate the parameters of the proposed phenomenological kinetic model. The analytical and numerical details related to the integration of the model are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01982684
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  • 9
    Electronic Resource
    Electronic Resource
    Degradation behaviour of a composite material for thermal protection systemsPart II Process simulation (1998)
    Springer
    Journal of materials science 33 (1998), S. 3145-3149 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Mass and energy balance equations have been solved in order to simulate the behavior of a silicon-based ablative composite used as a thermal protection shield for a non-animated space capsule. A method to calculate some of the parameters in the energy balance equation, is proposed, taking advantage of combined thermal analysis techniques. Furthermore, degradation kinetics in the hypothesis of constant volume is used to solve the mass balance. The results of the computer simulation are compared with the experimental data, obtained using plasma arc testing. The model can be used for both material selection and thickness calculation for thermal protection shields. © 1998 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004352007961
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  • 10
    Electronic Resource
    Electronic Resource
    Degradation behaviour of a composite material for thermal protection systems Part I–Experimental characterization (1998)
    Springer
    Journal of materials science 33 (1998), S. 3137-3143 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thermogravimetric studies and combined thermal analysis techniques have been used to characterize an ablative composite for thermal protection systems. The aim of the work was to utilize these techniques to obtain the main parameters used in the computer simulation of the space re-entry. In particular, a phenomenological model of the degradation kinetics of a silicon-based ablative composite has been developed using thermogravimetric analysis coupled with mass spectroscopic analysis. Simultaneous thermal analysis has also been used to calculate the ablation heat. The results are used as input for a computer model, developed in Part II, to enable calculation of the temperature profiles inside a thermal protection shield during the re-entry into the earth's atmosphere. Such a program can also be used in materials selection. © 1998 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004399923891
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