1. Oligomer synthesis Synthesis of the all-aromatic ester-based reactive liquid crystalline oligomers end-capped with phenylethynyl reactive end-groups. 1 DSC signals of the 5K oligomers series. First heat using a heating rate of 20 ºC/min. Melt behavior of the oligomers Thermal stability T g data were obtained from DMTA experiments and defined by the maximum of the E’’ peak. Introduction Thermal stability of the HBA/BP/TA(20)-9K cured thermosets, measured from room temperature to 600 ºC, under nitrogen atmosphere (red) and air atmosphere (blue), using a heating rate of 10 ºC/min. Conclusions and future Work Liquid crystal thermosets are a unique sub-set of high-performance polymers that combine desirable processing characteristics with outstanding thermo-mechanical properties after cure. LCTs are prepared via the so called reactive oligomer approach, where the oligomer backbone is terminated with latent end-groups that can react in a successive thermal post treatment step to form a network structure. In this work we have explored the most rigid, high Tg (~ 400 o C) LCT formulation known to data, i.e. based on 4-hydroxybenzoic acid (HBA), terephthalic acid (TA) and 4,4’-biphenol (BP). Herein we will discuss the thermo mechanical performance of these new polymers.  The reactive oligomer approach is an excellent method towards novel processable all- aromatic liquid crystalline polyesters based on all-para-substituted monomers (HBA/BP/TA).  High T g (> 350 o C) and high thermal stability (T d 5% (N 2 ) > 475 o C) make this class of polymers promising for demanding high-performance applications.  All cured polymers show excellent storage moduli (E’) as function of temperature and easily out performs PEKK.  Melt and cure rheology analyses are in progress.  One or two reactive oligomers will be selected and used as matrix in carbon fiber reinforced composites. Series 5000 g/mol - HBA/TA/BP 60%/20%/20% 50%/25%/25% 40%/30%/30% 30%/35%/35% Series 9000 g/mol - HBA/TA/BP 60%/20%/20% 50%/25%/25% 40%/30%/30% 30%/35%/35% Thermo-mechanical behavior Phase behavior Nematic textures of HBA/BP/TA(25)-9K observed by polarized microscopy. A– Low viscous sample at 370 ºC during cure. B– Crosslinked sample at 550 ºC after the complete cure. A B 5K Oligomers NitrogenAir 5% weight loss [ºC] Char yield 595 o C [%] 5% weight loss [ºC] HBA/BP/TA (20)48654482 HBA/BP/TA (25)49050475 HBA/BP/TA (30)49550484 HBA/BP/TA (35)48749475 9K Oligomers NitrogenAir 5% weight loss [ºC] Char yield 595 o C [%] 5% weight loss [ºC] HBA/BP/TA (20)49051484 HBA/BP/TA (25)49753484 HBA/BP/TA (30)49650488 HBA/BP/TA (35)49148486 5K OligomerOnset Temperature [ºC]Peak maximum (T K-N )[ºC] HBA/BP/TA (20)252311 HBA/BP/TA (25)290327 HBA/BP/TA (30)301328 HBA/BP/TA (35)304332 9K OligomerOnset Temperature [ºC]Peak maximum (T K-N )[ºC] HBA/BP/TA (20)262316 HBA/BP/TA (25)306346 HBA/BP/TA (30)324353 HBA/BP/TA (35)328363 Samples Glass Transition Temperature T g [ºC] Storage modulus E’ at 300 ºC [GPa] 5K thermosets HBA/BP/TA (20)3780.65 HBA/BP/TA (25)4050.81 HBA/BP/TA (30)4190.79 HBA/BP/TA (35)427 0.95 9K thermosets Glass Transition Temperature T g [ºC] Storage modulus at 300 ºC [GPa] HBA/BP/TA (20)3570.59 HBA/BP/TA (25)380 0.44 HBA/BP/TA (30)4251.5 HBA/BP/TA (35)4300.75 Representative DMTA scan for HBA/BP/TA(35)-5K. The experiment was performed under a N 2 atmosphere using a heating rate of 2 ºC/min and a frequency of 1 Hz. DMTA data showing HBA/BP/TA(35)-5K film (red) and a commercial available polyether-ketoneketone (PEKK) sample (black). Aerospace Engineering High T g ester based liquid crystal thermosets: synthesis and characterization PhD Candidate: Martino Marchetti Department: ASM Section: Novel Aerospace Materials Supervisor: Prof. Theo Dingemans Promoter: Prof. Theo Dingemans Start date: 01-01-2013 1. Mazhar Iqbal, Theo J. Dingemans, European Polymer Journal, 2010, 46, 2174–2180.