Thermal bonding

Prior to thermal bonding the glass pieces should be cleaned and have to be positioned relatively to each other. After positioning the entire stack 

A sample of a joined three sheets device is shown in Fig. 10.4. An increase of temperature and of joining time favours the bonding process and the stability of the joint. Simultaneously the precision of the contours deteriorates. 

A partial joining of glass components is possible using thermal bonding by applying pressure selectively. The spring structure that is part of the middle sheet shown in Fig. 10.4 can oscillate freely. The structure was created 

A single chip combinatorial synthetic reactor was fabricated by thermal bonding three layers of Pyrex-glass for 5h at 650°C under pressure [273]. The glass-to-glass bonding of Pyrex substrates was also investigated by [418]. The 

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Thermal asphalt Thermal blacks Thermal bonding Thermal chlorination Thermal coatings Thermal comfort Thermal conductivity... 

In the spunbond process, the fiber is spun similarly to conventional melt spinning, but the fibers are attenuated by air drag appHed at a distance from the spinneret. This allows a reasonably high level of filament orientation to be developed. The fibers are directly deposited onto a moving conveyor belt as a web of continuous randomly oriented filaments. As with meltblown webs, the fibers are usually thermal bonded or needled (53). 

Olefin fiber is an important material for nonwovens (77). The geotextile market is stiU small, despite expectations that polypropylene is to be the principal fiber in such appHcations. Disposable nonwoven appHcations include hygienic coverstock, sanitary wipes, and medical roU goods. The two competing processes for the coverstock market are thermal-bonded carded staple and spunbond, both of which have displaced latex-bonded polyester because of improved strength, softness, and inertness. 

A needled felt, on the other hand, is a fabric composed of natural, synthetic, or a combination of natural and synthetic fibers physically interlocked by the action of a needle loom with or without combination of other textile fabrics and with or without suitable combination of mechanical work, chemical action, moisture, and heat, but without weaving, knitting, stitching, thermal bonding, or adhesives (16). 

Smooth surfaces are normally estabflshed by calendering, a process which subjects the fabric at the nip point(s) of two or more roUs to the influence of controlled time, temperature, and pressure. When calendering is used as a thermal-bonding process, the roUs are of the same dimension and composition and are independently driven. However, when calendering is used as a fabric finishing operation, the roUs are frequently of different dimensions and composition and are not always independently driven. 

Fig. 2. Typical stress—strain curves of nonwoven fabrics, where (—) is woven (-), thermally bonded nonwoven and (-), needle-punched...

Resia biaders may alternatively be appHed ia discreet poiats ia a pattern so as to immobilize fewer fibers and produce a softer fabric however, it is difficult to accurately control the diffusion of the resia, and the dryiag step requiremeats make it less attractive than thermal bonding. 

When a multiplicity of single-hole spinnerettes are assembled across a width, the plexifilaments produced can form a wide web that can be thermally bonded to produce a flat sheet stmcture (49). The web-forming procedure is amehorated by use of a baffle which deflects the stream of plexifilaments after exiting the spinnerette. 

Non-woven A porous web or sheet produced by mechanically, chemically or thermally bonding together polymers, fibers or filaments. 

Bag molding Hinterspritzen This patented process allows virgin or recycled TPs such as PP, PC/ABS, etc. to thermally bond with the backing of multilayer PP based fabrics providing good elasticity. This one step molding technique provides a low cost approach for in-mold fabric lamination that range from simple to complex shapes. 

Figure 7.44 Thermal bond rupture (a) fragmentation reaction, (b) oxidation degradation.

In the parallel-plate method, the heat flux downward is measured hy a fluxmeter under which the thermal bond material and the molten salt of interest are located. Because the thermal transfer is only conductive if the thermal contacts are perfect, the balance of heat flow through the... 

Figure 3.7 Alternated 90° turned adjacent platelets forming a stacked cross-flow configuration. Image of thermally bonded devices (top). Complete mounted multi-plate stack micro reactors (bottom) [45].

Microfabrication is achieved by photolithography and isotropic etching of glass using HF [4—13]. Thermal bonding serves for interconnection. Holes are drilled in the top plate for connection to the fluidic peripherals. 

Microfabrication was made by wet-chemical glass etching [20]. Sealing was achieved by thermal bonding. 

The whole system is constructed from two silicon wafers, fabricated using photoresist by deep reactive ion etching (DRIB) [21]. The wafers were thermally bonded. Thereafter, inlet and outlet ports were machined and the single reactors isolated by DRIB. 

Two microstructured layers of the 2x2 chip were fabricated by photolithography and wet etching in glass (Figure 4.11) [23,24]. These top and bottom layers and a third thinner layer containing holes as conduits were thermally bonded to yield the chip. The way of guiding the micro charmels, as described above, is referred to as two-level crossing. 

The chip is made from glass by photolithography and wet etching followed by thermal bonding. 

This chip version is typically made in glass and has the great advantage that the flow can be directly visualized [40,44—46]. Fabrication is achieved by photolithography and wet-chemical etching followed by thermal bonding of the plates covered with a thin layer of solder [47]. 

P 33] The catalyst bed was manually positioned in the micro channel (300 pm wide 115 pm deep) at room temperature using a 10% (v/v) solution offormamide and potassium silicate [6, 7]. Micro reactor bottom and top plates were thermally bonded thereafter. Then, 75% THF (aqueous) solutions of 4-bromobenzonitrile and phenylboronic acid having equimolar concentrations were placed in the two reservoirs of a micro-mixing tee chip. In the collection reservoir, 30 pi of the THF solution was placed. Voltages ranging from 100 to 400 V were used, but kept constant only for one reservoir. The other one was switched on and off at 200 V for given time periods. 

The solvent s role in the first step of the process is clearly based as much on dispersing and dissolving the coal molecules resulting from thermal bond breaking as it is on stabilizing the molecules by hydrogen transfer. 

Bondline readout, 7 122 Bond number (Bo), 15 687t Bond orientational order, of liquid crystalline materials, 15 85 Bonds, fullerene, 12 233-234 Bond strength, in thermal bonding, 17 510 Bone, 7 273t. See also Bones citric acid in, 6 632t Bone fractures, 3 725 treatment, 3 725... 

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