Yes / Chemical manufacturing typically requires more than one step, involving multiple batch processes, which makes synthesis at scale laborious and wasteful. Herein, we demonstrate that several reactions can be telescoped into a single continuous process and/or be carried out as a continuous multi-component reaction (MCR), by twin screw extrusion (TSE), in the complete absence of solvent. / EPSRC (EP/L019655/1).

Yes / A study on the translation of a solid-state synthetic reaction from a mechanochemical mixer-mill to a continuous twin-screw extruder is discussed herein. The study highlights some considerations to be made and parameters to be tested in the context of a model fluorination reaction, which is the first organic fluorination to be attempted using extrusion. Upon optimization, which features the first use of grinding auxiliary solids to enable effective synthetic extrusion, the difluorination reaction was successfully translated to the extruder, leading to a 100-fold improvement in Space Time Yield (STY); 29 kg m−3 day−1 in a mixer mill to 3395 kg m−3 day−1 in a twin screw extruder. / D. L. B is grateful to the EPSRC for a First Grant (D. L. B. EP/P002951/1), CRD for a studentship award to J. L. H., Queen’s University Belfast for a Visiting Research Fellowship and the School of Chemistry at Cardiff University for generous support. S. L. J. is grateful to EPSRC for support (EP/L019655/1).

No / Mechanochemical synthesis has been applied to the rapid synthesis of Deep Eutectic Solvents (DESs), including Reline 200 (choline chloride : urea, 1 : 2), in a continuous flow methodology by Twin Screw Extrusion (TSE). This gave products in higher purity and with Space Time Yields (STYs), four orders of magnitude greater than for batch methods

No / The oligomerisation of L-amino acids by papain was studied in a mixer ball mill and in a planetary ball mill. The biocatalyst proved stable under the ball milling conditions providing the corresponding oligopeptides in good to excellent yields and with a variable degree of polymerisation. Both parameters were found to be dependent on the reaction conditions and on the nature of the amino acid (specifically on its side-chain size and hydrophobicity). In addition, the chemoenzymatic oligomerisation was demonstrated by utilising twin-screw extrusion technology, which allowed for a scalable continuous process. Finally, the synthesised oligo(L-Leu) 2b proved to be active as a catalyst in the Juliá–Colonna enantioselective epoxidation of chalcone derivatives. / We acknowledge RWTH Aachen University for support by the Distinguished Professorship Program funded by the Excellence Initiative of the German federal and state governments. We kindly acknowledge Marcus Frings and Plamena Staleva for the HPLC analysis of products 4a–c (RWTH Aachen University) and ASEP for the TGA analysis (Queen’s University Belfast). D. E. C. and S. L. J. acknowledge the agency EPSRC, grant no. EP/R019655/1. Part of this work was performed at the Center for Chemical Polymer Technology (CPT) unit of DWI, which was supported by the EU and the federal state of North Rhine-Westphalia (grant EFRE 30 00 883 02).

Yes / The continuous and scalable synthesis of a porous organic cage (CC3), obtained through a 10-component imine polycondensation between triformylbenzene and a vicinal diamine, was achieved using twin screw extrusion (TSE). Compared to both batch and flow syntheses, the use of TSE enabled the large scale synthesis of CC3 using minimal solvent and in short reaction times, with liquid-assisted grinding (LAG) also promoting window-to-window crystal packing to form a 3-D diamondoid pore network in the solid state. A new kinetically trapped [3+5] product was also observed alongside the formation of the targeted [4+6] cage species. Post-synthetic purification by Soxhlet extraction of the as-extruded ‘technical grade’ mixture of CC3 and [3+5] species rendered the material porous. / Engineering and Physical Sciences Research Council (EPSRC) under the Grants EP/R005710/1 (AIC) and EP/R005540/1 (SLJ), and for an EPSRC Summer Vacation Bursary at the University of Liverpool (FG, RLG). We also thank the European Research Council under FP7, RobOT, ERC Grant Agreement No. 321156 (AIC), for financial support. RLG thanks the Royal Society for a University Research Fellowship.

No / The development and validation of a sensor for extrusion melt temperature field measurement is described. A grid of opposing thermocouple wires was constructed and held in position by a supporting frame. Wires were joined together at crossing points to form thermocouple junctions, which were computer monitored. The mesh was used to monitor melt temperature fields during single screw extrusion at the die entrance. Design and construction of the mesh is described in addition to experimental optimization of wire diameter and junction forming. Calibration of the sensor and potential measurement errors including shear heating effects are discussed. Initial results from single screw extrusion are presented for a commercial grade of low density polyethylene using five- and seven-junction thermocouple meshes. The dependence of melt temperature profile on screw speed is illustrated. At low screw speeds melt temperature profiles were flat in shape and higher than set wall temperatures. At higher screw speeds the profiles became more pointed in shape. Use of higher resolution sensors exposed more complex temperature profiles with shoulder regions.

No / Polymer extrusion is fundamental to the processing of polymeric materials and melt flow temperature homogeneity is a major factor which influences product quality. Undesirable thermal conditions can cause problems such as melt degradation, dimensional instability, weaknesses in mechanical/optical/geometrical properties, and so forth. It has been revealed that melt temperature varies with time and with radial position across the die. However, the majority of polymer processes use only single-point techniques whose thermal measurements are limited to the single point at which they are fixed. Therefore, it is impossible for such techniques to determine thermal homogeneity across the melt flow. In this work, an extensive investigation was carried out into melt flow thermal behavior of the output of a single extruder with different polymers and screw geometries over a wide range of processing conditions. Melt temperature profiles of the process output were observed using a thermocouple mesh placed in the flow and results confirmed that the melt flow thermal behavior is different at different radial positions. The uniformity of temperature across the melt flow deteriorated considerably with increase in screw rotational speed while it was also shown to be dependent on process settings, screw geometry, and material properties. Moreover, it appears that the effects of the material, machine, and process settings on the quantity and quality of the process output are heavily coupled with each other and this may cause the process to be difficult to predict and variable in nature. (C) 2013 Society of Plastics Engineers

Yes / Real time measurement of melt rheology has been investigated as a Process Analytical Technology (PAT) to monitor hot melt extrusion of an Active Pharmaceutical Ingredient (API) in a polymer matrix. A developmental API was melt mixed with a commercial copolymer using a heated twin screw extruder at different API loadings and set temperatures. The extruder was equipped with an instrumented rheological slit die which incorporated three pressure transducers flush mounted to the die surface. Pressure drop measurements within the die at a range of extrusion throughputs were used to calculate rheological parameters such as shear viscosity and exit pressure, related to shear and elastic melt flow properties respectively. Results showed that the melt exhibited shear thinning behavior whereby viscosity decreased with increasing flow rate. Increase in drug loading and set extrusion temperature resulted in a reduction in melt viscosity. Shear viscosity and exit pressure measurements were found to be sensitive to API loading. These findings suggest that this technique could be used as a simple tool to measure material attributes in-line, to build better overall process understanding for hot melt extrusion.

This research investigates formulation, compounding and thin-wall injection moulding of Polypropylene/clay nanocomposites (PPCNs) prepared using conventional melt-state processes. An independent study on single screw extrusion dynamics using Design of Experiments (DoE) was performed first. Then the optimum formulation of PPCNs and compounding conditions were determined using this strategy. The outcomes from the DoE study were then applied to produce PPCN compounds for the subsequent study of thin-wall injection moulding, for which a novel four-cavity injection moulding system was designed using CAD software and a new moulding tool was constructed based upon this design. Subsequently, the effects of moulding conditions, nanoclay concentration and wall thickness on the injection moulded PPCN parts were investigated. Moreover, simulation of the injection moulding process was carried out to compare the predicted performance with that obtained in practice by measurement of real-time data using an in-cavity pressure sensor. For the selected materials, the optimum formulation is 4 wt% organoclay (DK4), 4 wt% compatibiliser (Polybond 3200, PPgMA) and 1.5 wt% co-intercalant (erucamide), as the maximum interlayer spacing of clay can be achieved in the selected experimental range. Furthermore, DoE investigations determined that a screw speed of 159 rpm and a feed rate of 5.4 kg/h are the optimum compounding conditions for the twin screw extruder used to obtain the highest tensile modulus and yield strength from the PPCN compounds. The optimised formulation of PPCNs and compounding conditions were adopted to manufacture PPCN materials for the study of thin-wall injection moulding. In the selected processing window, tensile modulus and yield strength increase significantly with decreasing injection speed, due to shear-induced orientation effects, exemplified by a significantly increased frozen layer thickness observed by optical microscopy (OM) and Moldflow® simulation. Furthermore, the TEM images indicate a strong orientation of clay particles in the flow direction, so the PPCN test pieces cut parallel to the flow direction have 36.4% higher tensile modulus and 13.6 % higher yield strength than those cut perpendicular to the flow direction, demonstrating the effects of shear induced orientation on the tensile properties of thin-wall injection moulded PPCN parts. In comparison to injection speed, mould temperature has very limited effects in the selected range investigated (25-55 °C), in this study. The changes in moulding conditions show no distinctive effects on PP crystallinity and intercalation behaviour of clay. Impact toughness of thin wall injection moulded PPCN parts is not significantly affected by either the changes in moulding conditions or clay concentration (1-5 %). The SEM images show no clear difference between the fracture surfaces of PPCN samples with different clay concentrations. TEM and XRD results suggest that higher intercalation but lower exfoliation is achieved in PPCN parts with higher clay content. The composites in the thin sections (at the end of flow) have 34 % higher tensile modulus and 11 % higher yield strength than in the thicker sections, although the thin sections show reduced d001 values. This is attributed to the significantly enhanced shear-induced particle/molecular orientation and more highly oriented frozen layer, according to TEM, OM and process simulation results. In terms of the reduced d001 values in the thin sections, it is proposed that the extreme shear conditions in the thin sections stretch the PP chains in the clay galleries to a much higher level, compaction of clay stacks occurs as less interspacing is needed to accommodate the stretched chains, but rapid cooling allows no time for the chains to relax and expand the galleries back. Overall, data obtained from both actual moulding and simulation indicate that injection speed is of utmost importance to the thin-wall injection moulding process, development of microstructure, and thus the resulting properties of the moulded PPCN parts, in the selected experimental ranges of this research.

Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-15T17:17:43Z No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / Made available in DSpace on 2014-05-15T17:17:43Z (GMT). No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.