AFRL-RX-WP-JA-2017-0316 LARGE FORMAT ADDITIVELY MANUFACTURED TOOLING FOR OUT-OF-AUTCLAVE AEROSPACE COMPOSITES ( PREPRINT )
The aerospace composites industry is plagued with high costs and long lead times for tooling, driving up part costs and delaying design cycles in new production. Tooling also complicates sustainment efforts for the Air Force’s legacy aircraft. Large format additive manufacturing has the potential to address both issues. Printed thermoplastic tools in excess of 0.5 square meters in size will be presented that are capable of curing aerospace-quality epoxy and bismaleimide composites at lower cost and with much quicker lead times compared with conventional tooling. 3D-printable, high-temperature thermoplastics and reinforcing fibers will be investigated to achieve the right balance of strength, dimensional stability, and life from the tooling. A general approach for optimization of print parameters to achieve a high-quality tool will be explored. The ability of these additively manufactured tools to withstand autoclave cures as well as out-ofautoclave processes (some of which will require the tooling to support 7 kg/sq m (100 psi) single-side loading) will be demonstrated. The Air Force’s Low Cost Attritable Aircraft Technology (LCAAT) platform is especially suited for this technology and will be used as a demonstrator for this work.
Effect of Curing Poly( p -Phenylene Sulfide) on Thermal Properties and Crystalline Morphologies
Commercial poly(p-phenylene 
sulfide) (PPS) was thermally cured, which resulted in an increase of molecular 
weight due to cross-linking. Non-isothermal crystallization studies of samples 
cured for up to 7 days at 250?C showed a monotonous increase of crystallization 
temperature compared to pure PPS. However, a further increase of curing time decreased 
the crystallization temperature. The change in the half-crystallization time (t1/2) was similar to the 
crystallization temperature. Thus, the cross-linking of PPS affected 
crystallization behaviors significantly. To a certain 
extent, crosslinks acted as nucleation agents, but excessive cross-linking 
hindered the crystallization. Morphologies observed by polarized optical 
microscopy suggested that thermal curing for as little as 1 day contributed to 
the spherulitic structure having a smaller size, that was not observed with 
pure PPS.
Formation of unexpected ions from a first-generation polyamidoamine dendrimer by use of methanol: an artefact due to electrospray emitter corrosion?
We report the formation of unexpected ions during the analyses of a first-generation polyamidoamine dendrimer in negative ion mode using an ion trap equipped with an electrospray ionisation source. These surprising ions corresponded to an increase of 12 m/z units over those expected. The formation of the unexpected ions was dependent on the tuning of the solution flow rate and the capillary high voltage. In addition, measurements of unusual value of the current suggested that a reaction was occurring in the corona plasma. The influence of methanol in this phenomenon was demonstrated by using CD(3)OH in the sample preparation. We propose two structures to explain the observed adduct based on the results of MS(2) experiments and by referring to previous work dealing with 12 m/z units addition. We showed that a corona discharge caused by alterations taking place to the electrospray capillary emitter was the origin of these unexpected ions. Finally, we discuss the mechanism involved in the formation of the ions and we propose means to control such artefacts.