Technical documentation

Powder Injection Moulding and Extrusion

WO1995020609
By: 
Barry Hull
Colin Birkinshaw

A method of injection moulding or extruding an article is disclosed in which a ceramic and/or metallic powder is dispersed in a carrier to form a flowable composition. The carrier is preferably a monomeric cyanoacrylate which is reversibly polymerisable so as to yield a solid polymer, which in turn is capable of undergoing a thermally activated depolymerisation reaction so as to yield the monomeric species. The composition is injected into a mould or extruded through a die and the carrier polymerised in the mould or die.

Production of Sintered Nd-Fe-B Magnets with a Maximum Energy Density of 53 MGOe

By: 
W. Rodewald
R. Blank
B. Wall
G. W. Reppel
H. D. Zilg

New sintered Nd-Fe-B near net-shape magnets with a high remanent polarization of 1.47 T, a coercivity HcJ of 9.6 kA/cm (12 kOe) and a maximum energy density of 420 kJ/m3 (53 MGOe) can be manufactured by rubber isostatic pressing. The optimization of the remanent polarization by an improved alignment process of the powder particles results in a decrease of the coercivity by 0.4 kA/cm per 1 % ∆fφ for alignment coefficients fφ in the range 96 to 98 %. For alignment coefficients between 98 to 99 % the decrease of the coercivity even increases to about –1 kA/cm per % 1 ∆fφ.

The use of near-infrared spectroscopy for the cure monitoring of an ethyl cyanoacrylate adhesive

By: 
S. K. Tomlinson
O. R. Ghita
R. M. Hooper
K. E. Evans

Near-IR reflectance spectroscopy has been used to study the curing of ethyl cyanoacrylate adhesive on polished dental glass and microscope slide substrates. The effects of changing the glue film thickness and the type of substrate on the curing rate have been investigated whilst maintaining a constant humidity. The FTIR spectral data has been used to calculate and plot the extents of cure versus time for various film thicknesses.

Bond strength of experimental cyanoacrylate-modified dental glass ionomer cements

By: 
Jin I. Lim
Kook J. Lim
Ho N. Lim
Yong K. Lee

Glass ionomer cement (GIC) has been successfully used in dental field for more than 40 years. Despite numerous advantages of GIC, low bond strength and slow setting rate limited conventional GICs for use only at low stress-bearing areas. To improve bond strength to tooth, two kinds of cyanoacrylates such as ethyl 2-cyanoacrylate (EC) and allyl 2-cyanoacrylate (AC) were added in a commercial GIC. Changes in setting time of cyanoacrylate-modified GICs (CMGICs) according to the concentration of cyanoacrylates and/or p-toluene sulfonic acid (TSA) was investigated using a rheometer.

The post-curing technology for conductivity improvement of low- viscosity electrically conductive adhesives

By: 
Andrzej Moscicki
Tadeusz Sobierajski
Tomasz Falatb Jan Felba

Polymer electronics plays more and more important role nowadays, especially in flexible electronics. The progress is also reflected in packaging materials and technologies. Metallic solders are replaced by electrically conductive adhesives based on polymer’s matrix. Very high volume production also requires new methods of adhesive deposition. The ink-jet printing technology seems to be very promising for bumps making in Flip- Chip type interconnections. Unfortunately, the technology is only in its infancy.

Adhesive and Conductive - Inkjettable nano-filled inks for use in Microelectronics and Microsystems Technology

By: 
Edouard M. Meyer
Andreas Arp
Francesco Calderone
Jana Kolbe
Wilhelm Meyer
Helmut Schaefer
Manuela Stuve

The present work demonstrates feasibility of an inkjettable, isotropically electrically conductive adhesive in the form of a silver loaded resin with a 2-step curing mechanism. In the first step, the adhesive is dispensed (jetted) and precured leaving a “dry” surface. The second step consists of assembly and final curing. The 2-step cure system is based on a Acrylate-Epoxy-Resin matrix with very low viscosity, i.e., 3 mPas of newtonian properties. Spheroidal silver particles of high purity and a compatible organic coating have been loaded at 70% by weight.

Piezoelectric ink jet processing of materials for medical and biological applications

By: 
Jan Sumerel
John Lewis
Andy Doraiswamy
Leila F. Deravi
Sarah L. Sewell
Aren E. Gerdon
David W. Wright
Roger J. Narayan

Many advanced medical and biological devices require microscale patterning of cells, proteins, and other biological materials. This article describes the use of piezoelectric ink jet processing in the fabrication of biosensors, cell-based assays, and other microscale medical devices. A microelectromechanical system-based piezoelectric transducer was used to develop uniform fluid flow through nozzles and to prepare well-defined microscale patterns of proteins, monofunctional acrylate ester, sinapinic acid, deoxyribonucleic acid (DNA), and DNA scaffolds on relevant substrates.

In Vitro Model for the degradation of Alkylcyanoacrylate Nanoparticle

By: 
Rainer H. Müller
Catherine Lherm
Jens Herbert
Patrick Couvreur

A photometric assay was developed to study the surface erosion of polymeric nanoparticles. The hydrolytic degradation of polyalkylcyanoacrylate particles was studied in different environments (NaOH, buffer, cell culture medium and serum). The influence of particle modification on the degradation rate was assessed. Particularly, the effect of polymer coating for particle targeting and fluorescence labelling was investigated. From the absorption data, a t 50% and t 100% can be calculated for fast degrading particles and obtained by an extrapolation in case of a slow degradation process.

Inkjet Printing of Biomedical Adhesives

By: 
Anand Doraiswamy
Jan Sumerel
Jonathan Wilker
Roger J Narayan

Synthetic adhesives have largely displaced natural adhesives in the automotive, aerospace, biomedical, electronic, and marine equipment industries over the past century. We have demonstrated the thin film deposition of biological adhesives using piezoelectric inkjet technology. A MEMS based piezoelectric actuator was controlled to jet uniform fluid flow of the adhesive solution through the ink jet nozzles. Microscopic deposition of adhesives enables improved bonding for a range of advanced electronic and biomedical applications.

Inkjet Printing of Cyanoacrylate Adhesives

By: 
Anand Doraiswamy
Rene Crombez
Weidian Shen
Yuan-Shin Lee
Roger J. Narayan

In this study, we have demonstrated the use of piezoelectric inkjet printing to fabricate microscale patterns of Vetbond® n-butyl cyanoacrylate tissue adhesive. Optical microscopy, atomic force microscopy, nanoindentation, and a cell viability assay were used to examine the structural, mechanical, and biological properties of microscale cyanoacrylate patterns. The ability to rapidly fabricate microscale patterns of medical and veterinary adhesives will enable reduced bond lines between tissues, improved tissue integrity, and reduced toxicity.

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