Hysteresis measurements for characterizing the dynamic fatigue of R-SMC

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich. - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively

Properties of copper modified polyamide 12-powders and their potential for the use as laser direct structurable electronic circuit carriers

Three-dimensional molded interconnect devices (3D-MID) are commercially produced by the laser direct structuring (LDS)-method with a market share of over 50%. The process chain of this method starts with injection molding. The polymer of this part is functionalized with LDS-additives which allow the part to be laser structured subsequently. This technique is less suitable for prototypes and small-scale productions of 3D-MIDs because of its properties. Contrary to the injection molding process, the additive manufacturing (AM), such as powder bed based manufacturing processes, e.g. selective laser sintering (SLS), is a constantly emerging processing technology for the fabrication of prototypes and small-scale productions. It enables the tool-free manufacturing of highly complex parts. Unmodified polyamide 12 (PA 12), e.g. PA2200 (supplier: EOS GmbH) is most commonly used for the SLS of polymer parts. The LPKF Laser & Electronics AG in Garbsen, Germany, transferred the LDS -method to SLS-process. A standard SLS-polymer part is coated with a special paint, that contains the necessary LDS-additives. Once coated and dried, these parts can be laser direct structured similar to standard 3D-MIDs. In this study, the authors use copper particles in order to functionalize a standard polyamide 12 powder for laser activation and selective metallization. The study shows, that the addition of copper particles enables the laser direct structuring of polyamide 12. SLS-demonstrators were successfully laser activated and selectively metallized. Furthermore, the copper particles enhance the mechanical properties as well as the heat conductivity of polyamide 12

Thermoplastic elastomers. II. Poly(ether-ester-imide)s based on 1,4-diaminobutane, trimellitic anhydride, 1,4-dihydroxybutane,and poly(ethylene oxide)s

A series of new poly(ether-ester-imide)s, PEEIs, was prepd. from an imide dicarboxylic acid based on 1,4-diaminobutane and trimellitic anhydride. This imide dicarboxylic acid polycondensed with 1,4-dihydroxybutane formed the hard segments and poly(ethylene oxide), PEO-1000, or mixts. of PEO-1000 and poly(tetramethylene oxide), PTMO-1000, were used as soft segments. Whenever PTMO-1000 was used as comonomer, macrophase sepn. was obsd. at the end of the polycondensation. However, this macrophase sepn. had little influence on the mech. properties. A poly(ether-ester-imide), PEEI, contg. neat PEO-1000 was characterized by dynamic mech. thermoanal., stress-strain and hysteresis measurements, and by melt rheol. The mech. properties were compared with those of an analogous PEEI contg. neat PTMO-1000 and with those of a poly(ether-ester), PEE, based on poly(butylene terephthalate) hard segments and PTMO-1000. [on SciFinder (R)

Thermoplastic elastomers. III. Poly(ether-ester-imide)s based on 1,6-diaminohexane, trimellitic anhydride, 1,4-dihydroxybutane and poly(tetramethylene oxide)

An imide dicarboxylic acid was prepared from 1,6-diaminohexane and trimellitic anhydride and esterified with ethanol. This imide monomer was polycondensed with three different poly(tetramethylene oxide) diols (PTMO-650, PTMO-1000 and PTMO-2000) and with an excess of 1,4-dihydroxybutane. When PTMO-1000 was used, and even more when PTMO-2000 was used, a partial macrophase separation occurred at the end of the polycondensation process. The resulting poly(ether-ester-imide)s (PEEIs) were characterized by IR and 1H NMR spectroscopy, by viscosity and DSC measurements. Compared to thermoplastic elastomers based on poly(butylene terephthalate) these PEEIs crystallize slowly. Selected PEEIs were also characterized by dynamic melt rheology, by dynamic mechanical thermoanalysis, by stress–strain and by hysteresis measurements

Thermoplastic elastomers 1. Poly(ether-ester-imide)s based on 1,4-diaminobutane, trimellitic anhydride, 1,4-dihydroxybutane and poly(tetramethylene oxide) diols

Starting from 1,4-diaminobutane and trimellitic anhydride a bisimide dicarboxylic acid was prepd. which was transformed into its di-Et ester. This imide monomer was polycondensed with mixts. of 1,4-dihydroxybutane and poly(tetramethylene oxide) (PTMO) diols having no. av. mol. wts. (Mns) of 650, 1000 or 2000 Da. For each PTMO diol, the wt. fraction of the hard segments was varied from 30 over 40 and 50-60%. For the PTMO diols 1000 and 2000, macrophase sepn. was obsd. during polycondensation. This problem was solved in the case of PTMO-1000 by a PTMO diol of greater polydispersity. The chem. structure of the poly(ether-ester-imide)s, PEEIs, was characterized by IR and 1H NMR spectroscopy. The phase transitions were identified by DSC and DMTA measurements, which revealed that all members of this series were slowly crystg. materials. The mech. properties were detd. by stress-strain and hysteresis measurements. Macrophase sepn. during the polycondensation was reflected in poorer mech. properties. [on SciFinder (R)