3D打印高分子材料研究进展

主要介绍了聚乳酸(PLA),聚己内酯(PCL),聚醚醚酮(PEEK),聚碳酸酯(PC)和丙烯腈-丁二烯-苯乙烯塑料(ABS)等在3D打印技术中的应用,并且综述了这些材料相应的改性方法以及改性材料的应用性能。通过对已有3D打印材料的改性和扩充,3D打印产品将可以广泛应用到医疗、生物组织工程、工业、军事、航空航天等领域,3D打印技术也将成为一种主流的塑料加工技术。     

热塑性聚氨酯(TPU)3D打印研究进展

热塑性聚氨酯(TPU)具有高弹性和生物相容性,在工业和医疗领域中均得到了广泛应用,3D打印技术进一步拓展了TPU材料在医疗领域的应用。但是,热塑性聚氨酯的部分性能特点不利于3D打印成型,在一定程度上限制了其在3D打印中的应用,因此,需要对TPU材料进行改性。从3D打印工艺、工艺参数、专用材料、掺杂改性及先进应用领域研究5个方面,综述了TPU材料3D打印的国内外研究进展。介绍了FDM和SLS 2种可用于TPU材料3D打印的工艺方法,并且对国内外TPU打印材料力学性能与掺杂改性的研究现状进行了总结。同时,分析了TPU材料3D打印在鞋类加工和医学研究领域的应用发展,并且对3D打印TPU在医疗领域的应用前景进行了展望。     

Cf/SiC复合材料的原料高效改性及其3D打印制备研究进展

选用3D打印制备的碳纤维增强碳化硅陶瓷基（Cf/SiC）复合材料被广泛应用在航空航天、国防军事等重大领域。碳纤维（Cf）作为陶瓷基复合材料的主要候选增强体之一,由于表面惰性的存在,为了提高其与碳化硅（SiC）陶瓷基体的粘附性,对原料Cf的表面改性工作是十分必要的。粉末原料的高效改性制备是3D打印成型陶瓷的重要途径。本文综述了近年来国内外针对Cf改性的各种方法及特点,对Cf/SiC复合材料的3D打印成型及其高效制备方法进行归纳总结。     

聚己内酯3D打印成型工艺研究及力学性能分析

以聚己内酯（PCL）为材料,采用实验方法,研究了成型温度和打印层高对PCL制品翘曲变形的影响。通过三维（3D）打印制备PCL样条,表征了3D打印PCL的力学性能,并与注射成型进行对比。结果表明,随着成型温度的升高和打印层高的增加,PCL制品的翘曲变形量呈现出先增加后减小的趋势;PCL 的3D打印制品的拉伸强度、弯曲强度和断裂伸长率均高于传统注射成型工艺。     

3D打印用聚乳酸的改性及其应用研究进展

聚乳酸(PLA)具有独特的可生物降解性和生物相容性,是一种理想的3D打印材料。3D打印PLA材料应用广泛,特别是在生物医用领域。然而,PLA也存在着一些性能缺陷,在一定程度上限制了其在3D打印上的应用,因此需要对PLA进行改性。文章首先分析了PLA作为3D打印材料存在脆性大、耐热性差和易水解的性能缺陷;其次综述了3D打印PLA的改性方法,包括共聚改性、表面改性和共混改性;然后介绍了3D打印PLA材料的应用领域,包括生物医学领域和工业制造领域。最后文章介绍了具有优异耐热性和耐水解性的生物降解型立构聚乳酸,并对立构聚乳酸作为3D打印材料的前景进行了展望。     

PCL抑菌改性及其在肿瘤放疗体位固定器3D打印中的应用

选择聚己内酯(PCL)为基材,添加滑石粉和纳米氧化锌进行改性,采用双螺杆挤出机在温度150℃、转速250 r/min条件下制备PCL抑菌改性材料,研究了滑石粉用量对材料拉伸性能和流变性能的影响以及纳米氧化锌种类对材料抑菌性能的影响。结果表明,随着滑石粉含量增加,材料的拉伸强度逐渐增大,熔体流动速率(MFR)和断裂伸长率呈现先增大然后减小的变化趋势;当滑石粉含量(质量分数)为10%时,MFR和断裂伸长率到达最大值,分别为2.69 g/10 min和813%;平衡扭矩随之呈现先降低后增加的变化趋势,当滑石粉含量为10%时到达最小值3.2 N·m。在此基础上添加4种纳米氧化锌制备PCL抑菌3D打印材料,发现粒径为20～30 nm的纳米氧化锌对金黄色葡萄球菌和大肠杆菌的抑菌效果最佳。得到的最佳配方为:PCL 85%、纳米氧化锌4%、偶联增容改性剂YY–5021 1%和滑石粉10%,材料的MFR为2.5 g/10 min、拉伸强度为19.3 MPa、断裂伸长率为803%。将制备的PCL抑菌改性材料用于体位固定器的3D打印,在打印温度220℃、填充度100%、填充打印速度40 mm/s、底板温度30℃的条件下打印出外观良好、尺寸精准的体位固定器,其在肿瘤放疗体位固定领域具有良好的应用前景。     

3D打印改性聚乳酸性能研究进展

3D打印在近年来受到普遍关注,聚乳酸(PLA)作为一种在3D打印中最常见的材料,被广泛地使用。综述3D打印改性PLA材料的研究进展及其在多个领域的应用。介绍3D打印的基本工作原理、特点、PLA材料的性质及PLA作为3D打印材料的优势。分析物理改性和化学改性方法对3D打印PLA材料的力学性能、热稳定性、导电性、弹性和抗菌性的影响。总结打印方向、打印层高、打印温度、打印速度等工艺参数对3D打印PLA制品质量的影响。概括3D打印PLA在医学领域、工业领域和其他领域的应用,指出3D打印PLA材料面临的技术问题以及挑战,并提出其在今后的改进方向。     

一种3D打印光敏树脂的研制及性能

以改性环氧丙烯酸酯为预聚物,采用自由基-阳离子杂化聚合法制备了可在405 nm光照下固化的3D打印光敏树脂。研究了预聚物、稀释剂、光引发剂的含量对光敏树脂力学性能、黏度和体积收缩率的影响。结果表明,当光引发剂添加量为4%时,力学性能最优化;当改性环氧丙烯酸酯含量在48%~58%时,该体系能满足3D打印光固化材料的使用要求;采用本方法制备的光敏树脂具有卓越的热稳定性。     

3D打印成型工艺及PLA材料在打印中的应用最新进展

着重分析了熔融沉积成型、选择性激光烧结、立体光固化、分层实体制造等3D打印成型工艺基本原理及其各自的优缺点;综述了在不同的3D打印成型过程中对PLA材料的改性要求;系统论述了3D打印PLA材料在生物医学、机械制造、铸造加工、日常生活等领域的应用现状及最新进展,并对未来3D打印PLA材料及相关技术进行了展望。     

长、短碳纳米管改性PCL柔性复合材料

利用熔融沉积制造(FDM) 3D打印技术构建聚己内酯(PCL)基柔性电子结构单元应用于生物医学领域，是未来柔性器件发展的一个新方向。选用PCL作为柔性基体不仅可以满足FDM 3D打印工艺的需求，而且可以满足柔性电子材料在大形变可穿戴器件及生命健康监测领域应用的需求。采用长碳纳米管(LCNTs)、短碳纳米管(SCNTs)改性PCL基柔性复合材料，研究了SCNTs,LCNTs以及复配的SCNTs/LCNTs添加量对PCL基柔性复合材料力学、电学性能的影响。结果表明，当PCL基体中掺入CNTs (CNTs≤5wt.%)时，无论是LCNTs,SCNTs还是复配SCNTs/LCNTs的掺入，均可以明显地提升PCL基柔性复合材料力学及电学性能，且LCNTs的掺入量以及掺入比对PCL基柔性复合材料的力学以及电学性能的影响较为显著。当3wt.%≤CNTs≤5wt.%，此具有良好电学及力学性能的PCL/CNTs系列柔性复合材料适合制作大形变、高灵敏性柔性导电线材。     

Evaluation of the Usability of a Low-Cost 3D Printer in a Tissue Engineering Approach for External Ear Reconstruction

The use of alloplastic materials instead of autologous cartilage grafts offers a new perspective in craniofacial reconstructive surgery. Particularly for regenerative approaches, customized implants enable the surgeon to restore the cartilaginous framework of the ear without donor site morbidity. However, high development and production costs of commercially available implants impede clinical translation. For this reason, the usability of a low-cost 3D printer (Ultimaker 2+) as an inhouse-production tool for cheap surgical implants was investigated. The open software architecture of the 3D printer was modified in order to enable printing of biocompatible and biologically degradable polycaprolactone (PCL). Firstly, the printing accuracy and limitations of a PCL implant were compared to reference materials acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). Then the self-made PCL-scaffold was seeded with adipose-tissue derived stem cells (ASCs), and biocompatibility was compared to a commercially available PCL-scaffold using a cell viability staining (FDA/PI) and a dsDNA quantification assay (PicoGreen). Secondly, porous and solid patient-customized ear constructs were manufactured from mirrored CT-imagining data using a computer-assisted design (CAD) and computer-assisted manufacturing (CAM) approach to evaluate printing accuracy and reproducibility. The results show that printing of a porous PCL scaffolds was possible, with an accuracy equivalent to the reference materials at an edge length of 10 mm and a pore size of 0.67 mm. Cell viability, adhesion, and proliferation of the ASCs were equivalent on self-made and the commercially available PCL-scaffolds. Patient-customized ear constructs could be produced well in solid form and with limited accuracy in porous form from all three thermoplastic materials. Printing dimensions and quality of the modified low-cost 3D printer are sufficient for selected tissue engineering applications, and the manufacturing of personalized ear models for surgical simulation at manufacturing costs of EUR 0.04 per cell culture scaffold and EUR 0.90 (0.56) per solid (porous) ear construct made from PCL. Therefore, in-house production of PCL-based tissue engineering scaffolds and surgical implants should be further investigated to facilitate the use of new materials and 3D printing in daily clinical routine.     

Structural Evolution of PCL during Melt Extrusion 3D Printing

Screw‐assisted material extrusion technique is developed for tissue engineering applications to produce scaffolds with well‐defined multiscale microstructural features and tailorable mechanical properties. In this study, in situ time‐resolved synchrotron diffraction is employed to probe extrusion‐based 3D printing of polycaprolactone (PCL) filaments. Time‐resolved X‐ray diffraction measurements reveals the progress of overall crystalline structural evolution of PCL during 3D printing. Particularly, in situ experimental observations provide strong evidence for the development of strong directionality of PCL crystals during the extrusion driven process. Results also show the evidence for the realization of anisotropic structural features through the melt extrusion‐based 3D printing, which is a key development toward mimicking the anisotropic properties and hierarchical structures of biological materials in nature, such as human tissues.     

3D打印用ABS丝材性能研究

以丙烯腈–丁二烯–苯乙烯塑料(ABS)为基体,分别以碳酸钙、短切玻璃纤维(GF)和色母粒为改性填料,通过挤出成型制备改性ABS丝材,然后采用3D打印技术中的熔融沉积成型(FDM)技术,通过FDM型3D打印机打印测试试样,对其力学性能及收缩率展开研究。研究结果表明,碳酸钙填料的加入使得ABS 3D打印试样的拉伸强度降低,用量为2份的短切GF可略微提高试样的拉伸强度,但随着GF含量的增加拉伸强度下降;当打印速度不高于50 mm/s时,相比于橘黄色母粒,蓝色母粒可提高试样的拉伸强度;改性ABS试样的拉伸性能随着打印速度的增加呈现两种不同的变化趋势,这可能由材料流动性能的差异所引起;随碳酸钙或GF用量增加,试样的收缩率逐渐降低,其中GF改性ABS试样收缩率的降低幅度更大,相比于橘黄色母粒,蓝色母粒的加入能够更有效地降低ABS试样的收缩率。     

Fabrication of PCL/β‐TCP scaffolds by 3D mini‐screw extrusion printing

Scaffolds of polycaprolactone (PCL) and PCL composites reinforced with β‐tricalcium phosphate (β‐TCP) were manufactured aiming potential tissue engineering applications. They were fabricated using a three‐dimensional (3D) mini‐screw extrusion printing, a novel additive manufacturing process, which consists in an extrusion head coupled to a 3D printer based on the Fab@Home equipment. Thermal properties were obtained by differential scanning calorimetry and thermogravimetric analyses. Scaffolds morphology were observed using scanning electron microscopy and computed microtomography; also, reinforcement presence was observed by X‐ray diffraction and the polymer chemical structure by Fourier transform infrared spectroscopy. Mechanical properties under compression were obtained by using a universal testing machine and hydrophilic properties were studied by measuring the contact angle of water drops. Finally, scaffolds with 55% of porosity and a pore size of 450 μm have shown promising mechanical properties; the β‐TCP reinforcement improved mechanical and hydrophilic behavior in comparison with PCL scaffolds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43031.     

3D printing of polycaprolactone/bioactive glass composite scaffolds for in situ bone repair

3D printing technology can fabricate customized scaffolds based on patient-derived medical images, so it has attracted much attention in the field of developing bone repair scaffolds. Polycaprolactone (PCL) is a suitable polymer for preparing bone repair scaffolds because of its good biocompatibility, thermal stability, excellent mechanical properties and degradable properties. However, PCL is a bioinert material and cannot induce new bone formation at the defect site. In this study, the bioactive material 58s bioactive glass was mixed into PCL to form PCL/bioactive glass composite material. The results of contact angle showed that the hydrophilicity of the scaffold was significantly enhanced with the increase of bioactive glass content. In vitro experiment results showed that, with the increase of bioactive glass content, cell adhesion and proliferation were enhanced, the expression levels of Runx2 and Collagen I(COL-I) were upregulated. The experimental results of in vivo radial defect repair in rats also showed that the effect of bone repair was improved with the increase of bioactive glass content. In conclusion, PCL customized bone repair scaffold containing 20% bioactive glass has widely potential used in the field of clinical bone repair.     

Sandwich-Like Gelatin/Polycaprolactone/Polyvinyl Pyrrolidone 3D Model with Significantly Improved Cartilage Cells Adhesion and Regeneration

A novel sandwich-like composite 3D model integrated with deposited gelatin film and printed polycaprolactone (PCL)/polyvinyl pyrrolidone (PVP) scaffold is proposed for 3D cartilage cell culture. The 3D model includes three layers, top scaffold, middle gelatin film, and basal slide. The printed scaffold layer mimicking extracellular matrix is employed to provide 3D regeneration architecture; gelatin film layer is used for fixing printed scaffold and catching falling cells. Electrospray and electrohydrodynamic jet printing technologies are combined to construct sandwich-like composite 3D model. The blended constructing processes are investigated thoroughly both theoretically and experimentally. The retained charges on the gelatin film are influenced the electric field distribution and jet behaviors during printing. The characteristics of gelatin film and composite scaffold are studied. The thickness, surface roughness, and planeness of one layer of deposited gelatin film are 400 nm, 22 nm, and 2.27 µm; the size of printed PCL/PVP composite fiber is 10 µm. The fabricated sandwich-like composite 3D model is proved to facilitate adhesion and ingrowth of cartilage cells.     

Preparation,properties, and laser processing of poly(ɛ-caprolactone)/poly(lactic acid) blends with addition of natural fibers as a potential for printing plates application

In this research, biodegradable blend of poly(ɛ-caprolactone) (PCL) and poly(lactic acid) (PLA) is proposed as a new material for the production of a printing plate for embossing process. Printing plates for embossing consist of raised printing elements and recessed nonimage elements. In production of printing plates, laser technology was used in order to form a relief printing plate. The embossing process is based on the principle of the pressure of the relief printing plate into the printing substrate, which causes the controlled deformation of the substrate and three-dimensional (3D) effect. Coir fibers (CFs) were added as a natural filler to PCL/PLA blends to improve and adjust the properties of produced blends. Scanning electron microscopy micrographs, dynamic mechanical analysis analysis, roughness, and hardness were measured on prepared materials, and 2D and 3D microscopy was conducted on laser engraved printing plates. Results have shown that the addition of CFs improved the mechanical properties of produced materials. DMA results indicate the semicrystalline structure of all prepared blends, and that the addition of CFs raises the elasticity of the composites. Laser engraving showed that it is possible to engrave the produced biodegradable materials and to use it as a material for production of printing plates.     

Toughening PVC with Biocompatible PCL Softeners for Supreme Mechanical Properties,Morphology, Shape Memory Effects,and FFF Printability

In this article, a first of its kind blend of polyvinyl chloride (PVC) and biocompatible polycaprolactone (PCL) is introduced by melt mixing and then 3D printed successfully via Fused Filament Fabrication (FFF). Experimental tests are carried out on PCL-PVC blends to assess thermo-mechanical behaviors, morphology, fracture toughness, shape-memory effects and printability. Macro and microscopic tests reveal that PVC-PCL compounds are miscible due to high molecular compatibility and strong interaction. This causes extraordinary mechanical properties specially for PVC-10 wt% PCL. In addition to the desired tensile strength (45 MPa), this material has a completely rubbery behavior at ambient temperature, and its total elongation is more than 81%. In addition, due to the high formability of PVC-PCL at ambient temperature, it has capability of being programed via different shape-memory protocols. Programming tests show that PVC-PCL blends have an excellent shape-memory effect and result in 100% shape recovery. SEM results prove a high improvement of PVC printability with the addition of 10 wt% PCL. Toughened PVC by PCL is herein added to the materials library of FFF 3D printers and expected to revolutionize applications of PVC compounds in the field of biomedical 3D and 4D printing due to its appropriate thermo-mechanical properties, supreme printability, and excellent biocompatibility.