RSC Advances
·
2018
·Vol. 8
·期 52
·29583-29588
·
IF 2.936
Rongping Ni,Bin Qian,Chang Liu,Xiaofeng Liu,Jianrong Qiu
Compared with parts fabricated via traditional methods, such as injection or compression molding, polymeric parts produced by 3D stereolithography (SLA) have poorer mechanical properties. Here, we demonstrate a cross-linking strategy used in the coating field to attain long chains for resin pre-polymerization to obtain final resin parts which can expand the application of SLA. Isophorone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol (PEG)-based prepolymer have long chains, making it easier for them to form dense structures. However, the prepolymer has high viscosity and can solidify in the absence of a laser. Thus, three kinds of adjuvants were added to dilute the prepolymer to make the slurry suitable for 3D-printing. Slurries were cured with different laser powers and scanning speeds. Diluents are found to affect the curing properties differently. With the diluent 2-hydroxyethyl acrylate added into the prepolymer, shrinkage of printed parts is lower than 1.3%. With the diluent ethylene glycol monophenyl ether, the density range of printed parts is between 1.187 g cm−3 and 1.195 g cm−3, which is higher than that of commercial PVC and PET. The three resins vary in density and hardness within a small range when the scanning speeds change. A relatively flat surface, high density and hardness can be obtained when the laser power is at 195.5–350 mW. Resin with this cross-linking strategy can expand the underutilized stereolithography's application from prototyping to actual parts by producing more functional components with excellent performance.
研究领域:
材料科学
·
3D打印技术
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 100
·82429-82437
·
IF 3.84
Yi Xu,Qichao Ran,Chao Li,Rongqi Zhu,Yi Gu
In this paper, the prepolymerization of acetylene-functional benzoxazine was carried out by using nickel acetylacetonate hydrate/triphenyl phosphine as a catalyst at a low temperature. By this method, the reaction heat of acetylene polymerization was partially released and no ring-opening polymerization of benzoxazine occurred. After that, the prepolymer was cured stepwise to obtain the cured product according to a traditional curing process. As a comparison, another cured product was directly obtained from acetylene-functional benzoxazine by the traditional method without prepolymerization. The curing behaviors and the thermal properties of these two polybenzoxazines were investigated and compared by FTIR, DSC, DMA, and TGA. Their thermal decomposition behaviors were further studied by TGA-FTIR, Py-GC/MS, and SEM. The results show that the catalytic prepolymeriztion makes the whole curing process milder and more controllable in a broader processing window. Furthermore, more crosslinked-polyacetylene structures and benzene from the catalytic prepolymerization improve the thermal stability of the polybenzoxazines. Additionally, less amine compounds were detected in the prepolymerization system during the thermal decomposition process and the appearance of the residue was stable and controllable after pyrolysis.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Yinming Fan,Guolong Zeng,Xiaoguo Ma
This work systematically investigated the effects of prepolymerization on the property of multi-templates surface molecularly imprinted polymer (MIP), which was utilized to quickly and simultaneously separate and detect six sulfonamides (sulfadiazine, sulfathiazole , sulfamerazine , sulfamethazine , sulfamethoxazole and sulfadoxine) in real waters. The MIPs were prepared using the six sulfonamides as the templates, mesoporous silica supported onto the surface of magnetic graphene oxide as the carrier and 4-vinylbenzoic as the functional monomer , with and without prepolymerization of templates with functional monomer. The preparation and adsorption conditions were optimized. It was found that the adsorption capacities of the selected six sulfonamides on the MIP (pre) prepared with prepolymerization were apparently higher than those on the MIP (no pre) synthesized without prepolymerization. Subsequently, the MIPs were utilized as adsorbents for SPE of these sulfonamides, and coupled with high performance liquid chromatography (HPLC) for the determination of sulfonamides. The developed analytical method showed outstanding applicability for the detection of trace sulfonamides in real water samples. The spiked recoveries and relative standard deviations (RSDs) of the six sulfonamides using MIP (no pre) and MIP (pre) were 73.34–99.43% and 87.37–102.34%, 2.28–7.77% and 3.18–6.49%, respectively.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2014
·
IF 4.384
Yilin Wu,Ming Yan,Yongsheng Yan,Xinlin Liu,Minjia Meng,Peng Lv,Jianming Pan,Pengwei Huo,Chunxiang Li
Inspired by a surface functional monomer-directing prepolymerization system, a straightforward and effective synthesis method was first developed to prepare highly regenerate and perm-selective molecularly imprinted composite membranes of artemisinin (Ars) molecules. Attributing to the formation of the prepolymerization system, Ars molecules are attracted and bound to the membrane surface, hence promoting the growth of homogeneous and high-density molecular recognition sites on the surface of membrane materials. Afterward, a two-step-temperature imprinting procedure was carried out to prepare the novel surface functional monomer capping molecularly imprinted membranes (FMIMs). The as-prepared FMIMs not only exhibited highly adsorption capacity (11.91 mg g–1) but also showed an outstanding specific selectivity (imprinting factor α is 4.50) and excellent perm-selectivity ability (separation factor β is 10.60) toward Ars molecules, which is promising for Ars separation and purification.
研究领域:
材料科学
·
药物化学
·
分离技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Xiaofeng Li,Min Wu,Xuechen Xiang,Zixin Ye,Ning Chen,Shiyu Ma
Hollow concave polymer particles have attracted wide attention due to their particular properties and applications, however, the controllable synthesis of hollow concave polystyrene nanoparticles (HC-PSNPs) based on soap-free emulsion polymerization via a one-pot method has not been achieved. Herein, based on a styrene/ethanol-water (St/EtOH-H 2 O) ternary system , a simple green self-templating dilution strategy was established to produce monodisperse HC-PSNPs. In the synthesis, the degree of concavity and opening size of HC-PSNPs can be controlled by adjusting polymerization parameters such as the pre-polymerization time (polymerization time before dilution) and dilution conditions (including dilution ratio and ethanol content of the diluents). Furthermore, one opening or multiple openings in the surface of HC-PSNPs can be controlled by varying the post-polymerization temperature (polymerization temperature after dilution). Based on our results and observations, we propose a plausible mechanism for the formation of HC-PSNPs.
研究领域:
材料科学
·
高分子化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）