Dynea (Norway)

Acid/base bi-functional polymeric materials were prepared using physically mixed porous polymers P(DVB-VBS) with sulfonic acid and P(DVB-VBA) with amino groups for various cascade reactions.

Abstract A comprehensive simulation model for urea/formaldehyde (UF)‐resins has been developed. The model utilizes kinetic results reported in the literature for low molecular weight systems and extends these to higher molecular weight systems by using a functional group approach. The model consists of‐ 9 functional groups, 5 urea groups and 4 formaldehyde groups.‐ 9 reactions, 5 methylolation reactions and 4 condensation reactions. In all these reactions both the formation and the decomposition reactions are included.All the kinetic constants are pH and temperature dependent.Two batch runs with different U/F ratios were used to adjust a couple of model parameters. Samples from these batch runs were analyzed with HPLC for low molecular weight compounds, and GPC for the average molecular weight. A run with continuous IR measurement showed excellent fit for the formaldehyde concentration. The model also estimates the viscosity from the functional groups.

Monosized superparamagnetic particles, Dynabeads®, have been used in various types of sample preparation including the isolation of cells, organelles, mRNA, genomic DNA and proteins. The magnetic beads can be used directly in crude samples such as whole blood and in 15–30 minute-protocols, the samples are purified by easy magnetic handling. The beads have also reached widespread use for analytical purposes such as solid-phase eDNA synthesis and RT-PCR, subtractive hybridization for the identification of cell-specific expression, cDNA selection for gene hunting, solid-phase sequencing, solid-phase footprinting for the characterization of DNA-binding proteins, and the specific capture of nucleic acid sequences such as viral genomes. In addition, the Dynabeads have proven to be well suited for automation which will be of importance for establishing molecular techniques in high throughput routine use such as medical diagnostics.

The method of activated swelling of polymer particles developed by the authors allows the preparation of monodisperse spherical beads of predictable size from 1 to 100 microns in diameter. The polymer particles may be prepared from a number of different monomeric materials and with various morphologies including macroporous structures. The porous beads form the basis for magnetizable monodisperse polymer particles which have magnetic iron oxides distributed as small grains all through the volume of the beads. The magnetic particles are being used extensively for selective cell separation and for immunomagnetic separation within microbiology and molecular biology. A review of recent work within these fields is given. New methods for positive cell separation are announced.

The formaldehyde release from particleboard under changing climatic conditions and with varying amounts of exposed particleboard was studied in a large climate chamber. A mathematical model was developed which describes the influence of the various parameters on the formaldehyde concentration in the atmosphere of a room containing particleboards. After determining the formaldehyde concentration under standard conditions by a laboratory method, the formaldehyde concentration under any other climatic conditions can be calculated. The mathematical relations presented in this paper are of model character, therefore, they cannot be transferred uneritically to every board system.