Green dimensional stability

Bulking Treatment with Water Insoluble Chemicals. The chief shortcomings of dimensional stabilization of wood with polyethylene glycol are that it can be leached from the wood and that the wood feels damp when held for prolonged periods of time at relative humidities of 80% and above. It thus appears desirable to deposit water insoluble materials within the cell walls of wood. This can be done by a replacement process with waxes (42). Water in green wood is replaced by Cellosolve (ethylene glycol monoethyl ether) by soaking the wood in this... 

Treatment of wood with polyethylene glycol (PEG) is the most commonly used method to impart dimensional stability to wood. PEG in a water solution can be used to permeate the lumens and penetrate the cell wall. A 30-50 percent solution of PEG in water generally is used on green wood no pressure is required. Treatment times are adjusted so that a uniform uptake of 25-30 percent of PEG is achieved, based on the dry weight of the wood temperatures range from 21 to 60°C. The wood may require weeks of soaking, depending on species, density, and thickness. After treatment, the wood is dried in a well-ventilated space, preferably heated. 

Ross RJ, McDonald KA, Green DW and Schad KC (1997) Relationship between log and lumber modulus of elasticity. Forest Products Journal, 47(2) 89-92 Rowell RM and Banks WB (1985) Water repellency and dimensional stability of wood. 

P. Nahass, W E. Rhine, R. L. Pober, and W L. Robbins, A Comparison of Aqueous and Non-Aqueous Slurries for Tape-Casting, and Dimensional Stability in Green Tapes pp. 355-64 in Ceramic Transactions, Vol. 15, Materials and Processes for Microelectronic Systems. Edited by K. M. Nair, R. Pohanka, and R. C. Buchanan. The American Ceramic Society, Westerville, OH, 1990. 

Coarse calcium carbonate with a broad particle size distribution, based on chalk, limestone or marble, or dolomite with an average particle size of approximately 15 pm, is the main filler used in PVC floor tiles. Price is the main specification but control of colour and of levels of coarse particles is needed. It is used as an extender at 200-450 phr. To give extra dimensional stability, reduced water pick-up, and green or hot strength during calendering and extrusion of the carpet high aspect ratio platy particles are used with the calcium carbonate. Stabilisation systems have to be modified to allow for the extra reactivity of the silicate surface. 

This product is a terpolymer of isobutylene isoprene and divinylbenzene, the latter giving a high degree of pre-cross-linking. The pre-cross-linking increases green strength, provides dimensional stability and reduces cold flow. This rubber is used as sealant. 

Dicaflock is an excellent filler for a wide variety of rubber and plastic products. Dicaflock iug>roves dimensional stability, reduces green shrinkage, improves ia act strength and improves drying rate of stable foams. 

To achieve dimensional stability in green sheets, they frequently undergo pressure treatment after casting. In this case the distance between particles is decreased due to the increased pressure, and the strength of the green sheet increases. 

Compatibility with fillers and oil Filler dispersion in soft compounds Dimensional stability and shape retention Green strength especially of heavily loaded compounds... 

Nahass P, Rhine WE, Pober RL, Bowen HK, Robbins WL (1990) A comparison of aqueous and non-aqueous slurries for tape-casting, and dimensional stability in green tapes. In Nair KM, Pohanka R, Buchanan RC (eds) Materials and processes in microelectronic systems, ceramic transactions, vol 15. American Ceramic Society, Westerville OH, pp 355-364... 

Monodisperse oligo(phenylenevinylene)s are assembled to three-dimensional scaffolds in convergent three- or fourfold Homer reactions of a silane core and stilbenoid aldehydes in moderate to good yields. The central silane is sensitive toward nucleophilic attack. Tetrahedral compounds with short side chains form stable amorphous films but trigonal-pyramidal shaped assemblies tend to recrystallize. The connection of the chromophores to a central silicon atom results in a stabilization of the excited states an intense blue-green fluorescence is emitted from solution as well as from transparent films. 

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