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Eco Requirements for Lubricant Additives and Base Stocks
Published in Leslie R. Rudnick, Lubricant Additives, 2017
Usually alcohols such as trimethylolpropane (TMP), neopentyl glycol (NPG), or pentaerythritol (PE) are used [52–54]. The corresponding acids for the esters can be either bio-based fatty acids or petrochemical acids. The resulting polyol esters show improved hydrolytic and thermal stability; the oxidation stability depends on the degree of saturation of the acid. From the saponification of fats and oils, different bio-based acids are available with carbon numbers from C-8 to C-22, fully saturated and highly unsaturated, respectively.
Rapid printing of nanoporous 3D structures by overcoming the proximity effects in projection two-photon lithography
Published in Virtual and Physical Prototyping, 2023
Harnjoo Kim, Rushil Pingali, Sourabh K. Saha
Custom photopolymer resists were synthesised by mixing polyfunctional acrylate monomers, a custom photoinitiator, and a radical inhibitor. The resist comprised a mixture of: (i) a mixture of pentaerythritol tetraacrylate, pentaerythritol triacrylate (PETA), and trimethylolpropane triacrylate that was sourced from Sigma Aldrich and had a refractive index of 1.483, (ii) bisphenol A ethoxylate diacrylate with average Mn ∼468 – EO/phenol 1.5 (BPADA) that was sourced from Sigma Aldrich and had a refractive index of 1.545, (iii) 4,4′-((1E,1′E)-(2-((2-Ethylhexyl)oxy)-5-methoxy-1,4-phenylene)bis(ethene-2,1-diyl))bis(N,N-dibutylaniline) that was procured from a commercial custom chemical synthesis service provider and which was synthesised from precursors as a photoinitiator following known literature procedures (Rumi et al. 2000), and (iv) additional 4-methoxyphenol (MEHQ) as a radical inhibitor. The monomer mixtures (i) and (ii) were mixed in a 35:65 ratio by weight to generate a monomer blend with a refractive index of 1.52 that closely matches the refractive index of the immersion medium of the objective lenses. This index-matched blend was used here to achieve sharp focusing through minimisation of spherical aberrations in the dip-in printing mode wherein the lens is directly dipped into the photoresist during printing (Mettry et al. 2021; Saha et al. 2018). The resists contained 0.1% by weight of the photoinitiator and 500 ppm of additional MEHQ.
3D-VAT printing of nanocomposites by photopolymerisation processes using amino-meta-terphenyls as visible light-absorbing photoinitiators
Published in Virtual and Physical Prototyping, 2023
Filip Petko, Emilia Hola, Magdalena Jankowska, Alicja Gruchała-Hałat, Joanna Ortyl
As monomers for cationic polymerisation, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (CADE, Sigma-Aldrich), Tri(ethylene glycol)divinyl ether (TEGDVE, Sigma-Aldrich), 1,4-cyclohexanedimethanol divinyl ether (1.4-CHMDE, BASF), 3-Ethyl-3-oxetanemethanol (S130, Lambson) were used. Trimethylolpropane triacrylate (TMPTA, AmBeed), Bisphenol A ethoxylate diacrylate (BEDA, Sigma-Aldrich) were used as monomers for free radical polymerisation experiments. Bis(4-t-butylphenyl)-iodonium hexafluorophosphate (IOD – Speedcure 938, Lambson Ltd), Ethyl 4-dimethylaminobenzoate (EDB, Alfa Aesar) and 2,4-Diethyl-9H-thioxanthen-9-one (THX, Sigma-Aldrich) were used as components of photoinitiating systems. Nanoparticles Aluminium oxide (Al2O3, Sigma Aldrich, nanopowder, 13 nm particle size) and Copper(II) oxide (CuO, Sigma Aldrich, nanopowder, <50 nm particle size) were used as filles for composites 3D-VAT printing. Structures of monomers and photoinitiating systems components are shown in Table S2 in Supporting Information.
3D printing of complex-shaped polymer-derived ceramics with enhanced structural retention
Published in Materials and Manufacturing Processes, 2022
Jian Liu, Shufeng Xiong, Hui Mei, Zhangwei Chen
The materials used in this study are shown in Table 1. Silres 604 (Waker, Germany) was selected as the silicone source for the resin solution. Tripropyleneglycol monomethyl ether, TPM (Aladdin, China) and tetrahydrofuran, THF (Aladdin, China) were used as solvents in the precursor resin. Trimethylolpropane triacrylate, TMPTA (Ryoji, Germany) and hexanediol diacrylate, HDDA (Ryoji, Germany) were selected as reactive diluents and monomers for the resin solution to improve the reactivity of the photosensitive polymerization process, and to provide the required strength for resin curing and fluidity during the printing process. Photoinitiator 819, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Jiazhong, China) was used as a free radical photoinitiator to initiate UV polymerization in unsaturated prepolymerization systems. Silicone oil I, polyhydroxy modified polyorganosiloxane (K-363B, Biaomei, China), silicone oil II, polyether modified polyorganosiloxane (SF-761 C, Biaomei, China), and silicone oil III, Polydimethylsiloxane (Sylgard 184, Dow Corning, USA) were used as the active additives in this work.