摘要:
An approach is provided in which a pH-indicating compound is incorporated in a printed circuit board. The printed circuit board includes a number of layers with the pH-sensitive indicator being incorporated in one of the layers. Conductive pathways are formed from a conductive sheet laminated onto an outer surface of the printed circuit board. The printed circuit board is exposed to a pH-activating solution. Plated-through hole defects in the printed circuit board are identified by detecting a color formation at a surface location of the printed circuit board that corresponds to the plated-through hole defect. Another approach is also provided where a pH-activating compound is incorporated in one of the layers of the printed circuit board which is then exposed to a pH-indicating solution to produce the color formation that identifies the location of the plated-through hole defect.
摘要:
An approach is provided in which a pH-indicating compound is incorporated in a printed circuit board. The printed circuit board includes a number of layers with the pH-sensitive indicator being incorporated in one of the layers. Conductive pathways are formed from a conductive sheet laminated onto an outer surface of the printed circuit board. The printed circuit board is exposed to a pH-activating solution. Plated-through hole defects in the printed circuit board are identified by detecting a color formation at a surface location of the printed circuit board that corresponds to the plated-through hole defect. Another approach is also provided where a pH-activating compound is incorporated in one of the layers of the printed circuit board which is then exposed to a pH-indicating solution to produce the color formation that identifies the location of the plated-through hole defect.
摘要:
An approach is provided in detecting plated-through hole defects in printed circuit boards (PCBs). The printed circuit board is exposed to a modified-silane solution. The modified-silane solution has a luminescent moiety and the modified-silane solution binds to exposed glass within a glass fiber layer of the printed circuit board. Plated-through hole defects are identified in the printed circuit board by detecting a luminescence at a surface location of the printed circuit board. Each surface location where the luminescence is detected corresponds to one of the plated-through hole defects.
摘要:
The present invention is directed to a reversibly adhesive thermal interface material for electronic components and methods of making and using the same. More particularly, embodiments of the invention provide thermal interface materials that include a thermally-reversible adhesive, and a thermally conductive and electrically non-conductive filler, where the thermal interface material is characterized by a thermal conductivity of 0.2 W/m-K or more and an electrical resistivity of 9×1011 ohm-cm or more.
摘要:
A method of determining that a thermoplastic was insufficiently dried before forming into a molded plastic part. The method comprises preparing a mixture of a thermoplastic polymer and an off-gassing compound, wherein the off-gassing compound is selected to release all water of hydration in response to target drying conditions specified for the thermoplastic polymer. The mixture is dried at actual drying conditions, and then heated to reduce the viscosity of the thermoplastic polymer and allow the mixture to flow. The mixture is then made to flow into a mold to form a plastic part at a molding temperature, wherein the molding temperature will cause any remaining water of hydration in the off-gas sing compound to off-gas and form surface irregularities in the plastic part. Non-limiting examples of the off-gassing compound include hydrated metal halides and ionic hydrates.
摘要:
Thermally cross-linkable photo-hydrolyzable inkjet printable polymers are used to print microfluidic channels layer-by-layer on a substrate. In one embodiment, for each layer, an inkjet head deposits droplets of a mixture of hydrophobic polymer and cross-linking agent in a pattern lying outside a two-dimensional layout of the channels, and another inkjet head deposits droplets of a mixture of poly(tetrahydropyranyl methacrylate) PTHPMA (or another hydrophobic polymer which hydrolyzes to form a hydrophilic material), cross-linking agent, and a photoacid generator (PAG) in a pattern lying inside the two-dimensional layout of the channels. After all layers are printed, flood exposure of the entire substrate to UV radiation releases acid from the PAG which hydrolyzes PTHPMA to form hydrophilic poly(methacrylic acid) PMAA, thereby rendering the PTHPMA regions hydrophilic. The layers of these now-hydrophilic patterned regions together define the microfluidic channels. The cross-linking agent (e.g., triallyl isocyanurate TAIC) forms covalent cross-links between the two polymer phases.
摘要:
An enhanced prepreg for printed circuit board (PCB) laminates includes a substrate and a resin applied to the substrate. The resin includes a curable polymer and a polymerization initiator polymer having a backbone with a free radical initiator forming segment that breaks apart upon being subjected to heat to generate a plurality of non-volatile initiating species. This resin composition eliminates possible volatile loss of the free radical initiator during all processing steps in the preparation of PCB laminates. The resin may additionally include a cross-linking agent, flame retardant and viscosity modifiers. In one embodiment, a sheet of woven glass fibers is impregnated with the resin and subsequently dried or cured. The glass cloth substrate may include a silane coupling agent to couple the resin to the substrate. In another embodiment, resin coated copper (RCC) is prepared by applying the resin to copper and subsequently curing the resin.
摘要:
A flame retardant capsule may contain a flame retardant, a polymer shell encapsulating the flame retardant, and at least one functional group orthogonal to the surface of the polymer shell. This flame retardant capsule may be covalently bonded into a polymeric material by the orthogonal functional group. The flame retardant capsules may be formed through microencapsulation.
摘要:
Thermal insulating materials and methods of making the thermal insulating material generally include a plurality of thermally reversible crosslinked polymer modified particles. The thermally reversible crosslinked polymer modified particles include a polymer containing a plurality of a first functional group; and a modified particle having a plurality of pendent cross-linking agents containing a second functional group, wherein the first functional group and the second functional group are complementary reactants to a reversible cross-linking reaction.
摘要:
A mechanism for fabricating microfluidic channels uses a three-dimensional inkjet printing unit to print the channels layer-by-layer on a substrate. In one embodiment, for each layer, an inkjet head deposits droplets of a hydrophobic material on a surface the substrate in a pattern lying outside a two-dimensional layout of the channels, and another inkjet head deposits droplets of a mixture of poly(tetrahydropyranyl methacrylate) PTHPMA (or another hydrophobic material which hydrolyzes to form a hydrophilic material) and a photoacid generator (PAG) on the surface of the substrate in a pattern lying inside the two-dimensional layout of the channels. After all layers are printed, flood exposure of the entire substrate to UV radiation releases acid from the PAG which hydrolyzes PTHPMA to form hydrophilic poly(methacrylic acid) PMMA, thereby rendering the PTHPMA regions hydrophilic. The layers of these now-hydrophilic patterned regions together define the microfluidic channels.