The use of natural (Pinus pinaster) resin in the production of printing ink and the printability effect

Alkyd resins are generally used in the production of printing inks. All industries look for alternative raw materials in the production of ink with the growing inclination toward using natural products. Resins forming the vehicle of the ink to be obtained from natural resources will provide benefits for the environment, nature, and living creatures. The aim of the study was to promote the use of natural resin in the ink system. Natural Pinus pinaster resin was added into vegetable and mineral oil-based solvents in pure form with alkyd resin in different amounts and ink varnishes of different combinations were prepared. Then, printing inks were produced from these varnishes in pure and hybrid form. Following the assessment of the rheological properties of the inks prepared, printing tests were conducted to assess the printing quality parameters. Ideal mixing ratios of the natural resins in the ink were determined for printability. The environmental importance and advantages of the use of natural resins were discussed. Recommendations were given in line with the results to encourage widespread use of natural resins in near future.     

Formation Theory and Printability of Photocurable Hydrogel for 3D Bioprinting

Bio-ink has gradually transited from ionic-crosslinking to photocrosslinking due to photocurable bio-hydrogel having good formability and biocompatibility. It is very important to understand and quantify the crosslinking process of photocurable hydrogels, otherwise, bioprinting cannot be standardized and scalable. However, there are few studies on hydrogel formation process and its photocrosslinking behavior which cannot be accurately predicted. Herein, the photoinitiated radical polymerized bio-hydrogels are taken as an example to establish the formation theory. Three typical crosslinking reactions are first distinguished. It is further proposed that not all double-bonds consumed during crosslinking contributeequally to polymerization. Then the concept of effective double-bond conversion (EDBC) is elicited. Deriving from EDBC, several important formation indices are defined. According to theory, it is predicted that slow crosslinking can improve the crosslinking degree. Furthermore, based on the slow crosslinking effect, a new strategy of projection-based 3D printing (PBP) is proposed, which significantly improved printing quality and efficiency. Overall, this work will fill the gap in hydrogel's formation theory, making it possible to accurately quantify the formation process.     

EIGA法制备激光3D打印用TA15钛合金粉末

采用电极感应熔炼气雾化(EIGA)法制备了激光3D打印用TA15钛合金粉末,研究了熔炼功率对粉末收得率、粒径分布、粉末形貌、松装密度和流动性等特征的影响。结果表明,随着感应熔炼功率增大,粉末收得率和平均粒径减小,当熔炼功率为65kW时,粉末收得率超过62%,中值粒径D_(50)小于100μm,松装密度为2.731g/cm3,流动性为22.46s/50g。对粒径50~180μm的粉末采用激光3D打印,激光直接沉积成形的TA15钛合金样品表面无宏观裂纹和气孔等缺陷,金相组织为细晶网篮组织,制备的TA15钛合金粉末具有良好的可打印性。     

纸张的印刷适性

纸张的印刷适性对印刷品的质量有着显著的影响，从纸张的平滑度、油墨吸收性、Z向变形、表面强度、光散射等几个方面论述了它们对印刷品质量的影响。     

3D打印再生砂浆的早期性能

研究了不同再生砂取代率对3D打印再生砂浆早期性能的影响,并通过在3D打印再生砂浆中加入不同掺量的超高分子量聚乙烯短纤维,探究了纤维掺量对再生砂浆打印性能的影响.结果表明：再生砂的掺入加速了3D打印再生砂浆早期强度的增长,50%、100%再生砂取代率的3D打印再生砂浆的湿坯强度增长速率分别是无再生砂砂浆的3.2、16.7倍;适量纤维的掺入不会影响再生砂浆早期强度的增长速率,而过多纤维的掺入将对再生砂浆早期强度的发展起负作用.     

矿物掺合料与化学外加剂对3D打印砂浆性能的影响

研究了矿物掺合料与化学外加剂对3D打印砂浆流变性能、凝结时间及打印性能的影响.结果表明:复掺矿粉与硅灰可显著改善打印砂浆的流变性能,延长打印砂浆的可操作时间,提高打印砂浆的打印性能;随着减水剂掺量的增加,打印砂浆的黏度、屈服应力及触变性均逐渐降低,凝结时间延长,减水剂掺量过低或过高均会对打印砂浆的打印性能产生不利影响;掺加适量缓凝剂可降低打印砂浆的黏度和屈服应力,改善其挤出性;随着石膏掺量的增加,打印砂浆的表观黏度、屈服应力、触变性及有效打印高度均呈现先降后增趋势,而挤出性变化规律与之相反.     

添加剂对3D打印轻骨料混凝土流变性和可打印性的影响

研究了骨料(石英砂、玻化微珠)、保塑剂(HMC)、塑化剂(KHC)、乳胶粉(FX)对3D打印轻骨料混凝土(3DPLAC)的流变性能、挤出性、堆积性能以及容重的影响.结果 表明:在相同水胶比下,随着玻化微珠取代量的增加,3D打印轻骨料混凝土的表观黏度、触变性和屈服应力明显下降,挤出性、堆积性能降低,容重显著下降;随着HMC和KHC掺量的增大,3D打印轻骨料混凝土的表观黏度、触变性、屈服应力均明显增大;随着FX掺量的增加,3D打印轻骨料混凝土的表观黏度、触变性以及屈服应力呈先减小后增大的变化趋势.通过优化各组分配比,3D打印轻骨料混凝土可获得适宜的流变性能,可打印性得到显著改善,容重明显降低.     

Diffusion of mineral oil in styrene‐butadiene polymer films

Mineral oil diffusion in styrene‐butadiene polymer films was investigated with a simple gravimetric sorption method. Over the selected range of temperatures and film thicknesses for which sorption tests were performed, the diffusion process is described in terms of Fick's third law. Polymer dissolution was found to compete with the diffusion process especially at high temperature. Possible interference due to dissolution on data generated using a gravimetric method, resulted in an estimation of apparent activation energy using diffusion coefficient set calculated with Crank's half‐time relationship. The mineral oil diffusion activation energy was found to be relatively high compared with those of hydrocarbons diffusing in natural and synthesized rubbers or crosslinked polybutadiene as reported in the literature. The influence of polymer T_g, crosslinking density, and polarity on mineral oil ability to penetrate polymer film was evaluated in terms of percent weight increase over time. Maximum absorption after 60‐min sorption time linearly correlates with mineral oil absorption rate for polymers prepared with different structures. This linear relationship suggests that diffusion of solvent in styrene‐butadiene polymers reveals the macroscopic composition and structural polymer modification rather than local changes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

凹凸棒土与纳米二氧化硅对高强石膏浆体3D可打印性的影响

本文研究了凹凸棒土(ATP)和纳米二氧化硅(NS)对3D打印用α半水石膏浆体泵送性、流变性、支撑性等可打印性及固化体力学强度的影响。结果表明,掺入ATP后,泵送力维持在(0.57±0.02) kN,浆体剪切应力与剪切应变曲线不随掺量增加而发生明显变化,0 h、4 h打印体坍塌角分别从空白组的24°、32°降至掺量为2.8%(质量分数,下同)时的8°、11°。与ATP相比,打印浆体掺加NS后泵送力明显增加,掺加2.8%NS浆体的泵送力是同掺量ATP浆体的近2倍,浆体剪切初始应力随NS掺量增加而增大。虽然掺加NS使浆体泵送阻力增大,NS较ATP对打印体的支撑性却明显提升,掺加2.8%NS打印体0 h、4 h均无明显坍塌。ATP和NS在1%~2%掺量时浆体均可打印,且固化打印体抗压强度均有所增加,但层间粘结强度均削弱约2/3。     

Tuning of ultraviolet-curable ink printability via in situ ultraviolet irradiation during direct ink write applications

Direct ink write deposition facilitates line-by-line extrusion of inks spanning wide viscoelastic ranges. Following deposition, post processing technologies permit tuning of the extrudate's material property characteristics—ultraviolet (UV) irradiation, facilitating the photopolymerization of UV-reactive catalyst solutions, permits targeted modification of the extrudate's microstructure and in situ tuning of extrudate macrostructure. This report analyzes the morphological, rheological, and microstructural property relationships governing the printability, and processivity, of extruded UV-curable resin inks for delineation of sufficiency and optimization of ink printability utilizing direct ink write technologies. A design-of-experiments approach is implemented to quantify significance regarding an extrudate's dimensional response to extrusion parameter variation and in situ processing parameters, identifying proportionally of nozzle velocity, nozzle height, and UV irradiation exposure with extrudate aspect ratio, reflected by respective maximum extrudate aspect ratio increases of 158% and 109%, regarding 121 and 123K resin inks. Finally, the relationship between extrudate morphology and microstructure variation was assessed via dielectric cure monitoring, whereby an extrudate's ion viscosity was calculated in relation to its rheological modulus, reflecting the relationship between an extrudate's morphology, rheological response, and printability, regarding its microstructural variation.