Cure Monitoring For Composites And Adhesives
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Cure Monitoring For Composites And Adhesives
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Author : David Mulligan
language : en
Publisher: iSmithers Rapra Publishing
Release Date : 2003
Cure Monitoring For Composites And Adhesives written by David Mulligan and has been published by iSmithers Rapra Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Science categories.
This report focuses on in-line cure monitoring as a key way of optimising production. The bulk of this review is devoted to coverage of the range of techniques used for cure monitoring. Consideration is also given to other topics relevant to the implementation of cure monitoring processes. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.
Cure Monitoring Techniques For Polymer Composites Adhesives And Coatings
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Author :
language : en
Publisher:
Release Date : 2005
Cure Monitoring Techniques For Polymer Composites Adhesives And Coatings written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Polymers categories.
Dielectric Cure Monitoring Of Composite Panels During Hot Pressing
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Author : Tyler G. Congleton
language : en
Publisher:
Release Date : 2001
Dielectric Cure Monitoring Of Composite Panels During Hot Pressing written by Tyler G. Congleton and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with Adhesives, Hot melt categories.
Dielectric quantification of material properties is a technology well established in many industries. The application of this concept to the forest products industry to measure adhesive cure, however, has been belated in part due to a lack of proven technology directed at industrial processes and products. It is of great interest to manufacturers to minimize production costs and maximize output. This means being able to identify the minimum time required to cure composite panel products during hot pressing. In the hot-pressing process, material is currently pressed based on a conservative schedule that is actually longer than necessary. The schedule provides what temperatures and pressures are to be used throughout the press cycle to ensure resin cure (cross-linking). In the case of urea-formaldehyde, the resin is subject to strength loss if heat remains applied too long. The objective of the schedule is to cure the resin to an acceptable level and remove the product before degradation can occur. It is difficult to exactly predict the optimum point given all the variables to consider such as panel thickness; moisture and time; press pressure and temperature; and particle geometry, etc. This is where dielectric monitoring can help. Since the critical variable is degree of resin cure, it is logical to design a monitoring system that measures and utilizes it in a feedback control system. As the resin is curing, the molecules and ions become interlaced in a lattice structure during polymerization, reducing rotational and migrational mobility. Rotational and migrational mobility can be quantified dielectrically by applying an oscillating electric field to the material. Included in any monitored dielectric quantity is the effect due to moisture and wood. Studies were conducted to determine their contribution to the readings. Particleboard panels were manufactured in a laboratory environment and monitored with a dielectric system developed by the author. Three different adhesives were used urea - formaldehyde (U F), phenol formaldehyde (PF), and polymeric diphenolmethane diisocyanate (isocyanate, MDI). Dielectric response curves were obtained for each of the resins, and internal bond strength (IB) measurements were taken throughout the curing process of the boards. IB data were charted with dielectric data to show characteristics in the dielectric response curves that could be used to indicate cure status. The dielectric response curves show very encouraging peaks, valleys, and inflection points that seem to correspond to respective cure data. These characteristics could be incorporated into a full-scale system and used in an industrial setting to control and optimize press operations.
In Situ Cure Monitoring And Characterization Of Graphite Epoxy Composites Using Fiber Optics And Ultrasonics
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Author : Jianyin Chen
language : en
Publisher:
Release Date : 1998
In Situ Cure Monitoring And Characterization Of Graphite Epoxy Composites Using Fiber Optics And Ultrasonics written by Jianyin Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Composite materials categories.
Advanced composites can be fabricated by laminating multiple plies into the desired shape, and then cured in an autoclave with simultaneous application of proper heat and pressure. The knowledge of the cure process is very important in order to obtain fully cured and high-quality composites. In-situ sensors capable of monitoring the change of physical and chemical properties during the cure process are therefore desirable. The major aspects of research in this thesis are as follows: The chemical kinetic and rheological properties of AS4/3501-6 Graphite/Epoxy composites are characterized by using Differential Scanning Calorimetry and Dynamic Mechanical Analyzer. This indicates that at 176°C, the cure reaction is almost fully completed after 60 minutes, and increasing cure temperature results in a noticeable decrease in loss tan 6 and a profound increase in the Tg. Ultrasonic characterization shows that the moduli of 3501-6 epoxy increase with increasing cure temperature, whereas the moduli of AS4/3501-6 composite reach their maximum around 176°C. Also, the moduli of the composite increase with increasing cure time, whereas the moduli of the epoxy, after being cured at 176°C for 80 minutes, exhibit no change. A state-of-the-art fiber-optic and ultrasonic cure processing monitoring system is developed, which consists of ultrasonic transducers with clad buffer rods, Extrinsic Fabry-Perot Interferometric fiber-optic sensors, and a special autoclave feedthrough. This system is workable in an autoclave at high temperature and gas pressure, has high ultrasonic signal to spurious noise ratio, and is suited for longitudinal and/or shear wave measurement. The development of properties of the curing AS4/3501-6 composite is monitored by using in-situ fiber-optic and/or ultrasonic sensors, indicating that (1) both sensors can sense the gelation period; (2) the ultrasonic sensor is able to determine the end-of-cure, while the fiber-optic sensor is not; (3) during the cool-down period the development of thermal mismatch strains between the mold plates and the composite panel, prior to and after the detachment, can be detected by the fiber-optic sensor.
Rapid Cure Composites
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Author : Nishar Hameed
language : en
Publisher: Elsevier
Release Date : 2023-05-17
Rapid Cure Composites written by Nishar Hameed and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-05-17 with Technology & Engineering categories.
Rapid Cure Composites: Materials, Processing and Manufacturing presents up-to-date information on the design criteria to formulate matrix systems for rapid curing. Emphasis is placed on the role different materials [resin compound and fiber reinforcement] play in developing fast curing composites, assessment of current and novel manufacturing techniques for adapting fast curing processes, the comparison between conventional curing and rapid curing, and different applications in various industrial sectors [e.g., aerospace, automotive, renewables and marine]. The book will be an essential reference resource for academic and industrial researchers working in the field of composite materials, processing and manufacturing organizations, materials scientists, and more. Polymer composites are widely used in several industries, including aerospace, automobile, spray and coatings, and electronics due to their lightweight and superior mechanical properties. However, one of the dominant hurdles towards their growth in commercial industries is the long curing cycle and slow production. Comprehensively addresses the scientific and technological development of rapid cured epoxy composites Covers, in detail, the chemistry, processing, structure and performance of rapid cured epoxy composites Provides detailed comparisons of how/why rapid cure composites are different to conventional composites Discusses the challenges of the existing technology and future trends
Handbook Of Polymer Blends And Composites
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Author : A. K. Kulshreshtha
language : en
Publisher: iSmithers Rapra Publishing
Release Date : 2002
Handbook Of Polymer Blends And Composites written by A. K. Kulshreshtha and has been published by iSmithers Rapra Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Technology & Engineering categories.
In Situ Cure Monitoring Of Graphite Epoxy Composites Using Fiber Optics And Ultrasonics
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Author : J.-Y. Chen
language : en
Publisher:
Release Date : 1998
In Situ Cure Monitoring Of Graphite Epoxy Composites Using Fiber Optics And Ultrasonics written by J.-Y. Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with categories.
Characterization And Cure Monitoring Of Structural Adhesives
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Author : Walter X. Zukas
language : en
Publisher:
Release Date : 1989
Characterization And Cure Monitoring Of Structural Adhesives written by Walter X. Zukas and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1989 with categories.
Two potential replacement adhesives for a discontinued commercial adhesive were investigated. The composition and curing behavior of the replacements were compared to the commercial system utilizing a number of analytical techniques. High performance liquid chromatography, size exclusion chromatography, and thermogravimetric analysis were applied to establish the lot-to-lot consistency of the adhesive component composition. The thermal, dynamic mechanical, rheological, and dielectric properties, as a function of cure, were monitored by differential scanning calorimetry, torsional braid analysis, parallel plate rheometry, and microdielectrometry, respectively. Correlations between the various techniques and the state of cure of the adhesive were made. The glass transition temperature of the adhesive was observed to be a very sensitive measure of the state of cure. Keywords: Adhesives, Characterization, Curing, Analytical techniques, Thermal analysis. (sdw).
Cure Monitoring Of Carbon Epoxy Composites Using Dielectrometry Technique
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Author : Jaspal singh B. Rawat
language : en
Publisher:
Release Date : 2004
Cure Monitoring Of Carbon Epoxy Composites Using Dielectrometry Technique written by Jaspal singh B. Rawat and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with categories.
Measuring Adhesive Cure By Dielectric Analysis
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Author : Robert Allen Rubitschun
language : en
Publisher:
Release Date : 1981
Measuring Adhesive Cure By Dielectric Analysis written by Robert Allen Rubitschun and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1981 with Adhesives categories.
Present methods of determining proper glueline cure are inadequate in either production or laboratory situations because they are time consuming and "after the fact". Monitoring the glueline while the wood composite is still in the press would provide many advantages over existing methods. Such a system would provide greater control over the degree of cure, helping eliminate variable quality in the glue bond. Dielectric spectroscopy has been proposed as a method capable of continuously monitoring adhesive cure and a specific machine, the Audrey II dielectrometer, has been advertised as being capable of detecting cure of resin systems common to the forest products industry. The objectives of this research were to determine if the Audrey II dielectrometer could measure cure of a highly caustic phenolic plywood adhesive and a resorcinol-formaldehyde laminating adhesive in Douglas-fir gluelines under conditions analogous to mill production. The dielectric spectrometer used in this study produced frequencies of 100-1000 Hz and measured voltage, capacitance, phase angle, and dissipation of the glued assembly placed between its electrodes. Capacitance was found to be the property that was most sensitive to changes in the wood-adhesive composite during the cure process. The dielectric spectrometer was able to accurately and consistently measure the capacitance of oven dried wood. Dielectric measurements were very sensitive to the presence of water, and the increase in capacitance with an increase in moisture content was reproducible. Problems were encountered when using the dielectric spectrometer to monitor cure of a resin in wood composites. The lack of repeatability in capacitance measurements led to the conclusion that the Audrey II dielectric spectrometer could not measure cure of a highly caustic phenolic adhesive or a resorcinolformaldehyde laminating adhesive in Douglas-fir gluelines. Components of a phenol-formaldehyde resin were examined to determine what caused the lack of reproducibility. The capacitance was reproducible with either water or aqueous caustic on the veneers. However, the presence of either phenol or formalin on the veneers resulted in a total lack of repeatability in capacitance. Both phenol and formalin are excellent swelling agents for wood and as wood swells, its microstructure is opened and plasticized. This would increase the capacitance. Other factors that would influence variation in swelling and capacitance would include depth of lathe checks, wood damage, porosity, density, and natural anatomical variation that influences the rate of penetration of chemicals into wood. Even considering the swelling effects and natural variation of wood, the variability in capacitance of the wood-adhesive composite is not readily understood.