查找使用阿拉丁产品的科研文献

Synergistic Flame-Retardant Mechanism of Dicyclohexenyl Aluminum Hypophosphite and Nano-Silica

Heng Zhang,Junliang Lu,Hongyan Yang,Heng Yang,Jinyan Lang,Qinqin Zhang

The flame retardant dicyclohexenyl aluminum hypophosphite (ADCP) and nano-silica are added to PA66 to improve flame retardant property of the composite. The flame-retardant property of the composite is tested via oxygen index test, vertical burning test, and cone calorimetry test. Combustion residues are tested using scanning electron microscopy, EDS spectroscopy, and Fourier infrared analysis. Results show that flame-retardant ADCP can effectively promote the formation of a porous carbon layer on the combustion surface of PA66. Nano-silica easily migrates to the material surface to improve the oxidation resistance of the carbon layer and the density of the carbon layer’s structure. It can also effectively prevent heat, flammable gases, and oxygen from entering the flame zone and enhance the flame retardant properties of ADCP.Keywords:nano-silica;ADCP;synergetic flame-retardant;PA66

In-situ thermal crosslinked PA66/β-cyclodextrin/PA66 nanofibrous membranes with high mechanical strength for removal of heavy metal ions by flow through adsorption

Yinchun Hu,Yizhu Cheng,Xuerong Zhang,Di Huang,Weiyi Chen,Menglan Duan

β-cyclodextrin (β-CD) based materials have been studied widely as adsorbents and filter membranes for removing pollutants in air or water applications. The present study aimed to develop a sandwich structure of eletrospun nanofibrous membrane based on β-cyclodextrin and PA66 to achieve the high mechanical strength and flow-through adsorption of heavy metal ions in water. The surface and cross section morphology of PA66/β-cyclodextrin/PA66 nanofibrous membranes (PA66/β-CD/PA66 NMs) were examined using scanning electron microscopy (SEM). The physicochemical and mechanical properties of PA66/β-CD/PA66 NMs were analyzed by differential scanning calorimetry (DSC), thermogravimetric (TG) analysis and universal testing machine. The diameter of β-CD and PA66 electrospun fibers are 300–400 nm and 20–40 nm respectively. PA66/β-CD/PA66 NMs show a loosely arranged fibers and layer by layer structure. The tensile strength increases remarkably for PA66/β-CD/PA66 NMs, from 1.33 MPa of β-CD NMs to 23.17 MPa and the Young's modulus increases from 34.8 MPa to 253.3 MPa. The mechanical behavior of PA66/β-CD/PA66 NMs is a typical brittle fracture , and its microcosmic fracture diagrams are also involved. TGA/DSC results confirm the thermal crosslinking reaction is effective and complete. On the basis of SEM, DSC, TG and mechanical behavior analysis results, the molecular mechanism of in situ thermal crosslinking reaction is discussed. Fe 3+ 、Ni 2+ were used to confirm the ability to absorb heavy metal ions of PA66/β-CD/PA66 NMs. In conclusion, PA66/β-CD/PA66 NMs could be a promising solution for removal of metal ions by flow-through adsorption.

Analysis of Microplastics in Aquatic Shellfish by Pyrolysis–Gas Chromatography/Mass Spectrometry after Alkali Digestion and Solvent Extraction

Yingying Zhong,Qibei Bao,Lifeng Yuan,Jiawen Liu,Yan Cai,Xianfeng Chen

Microplastics are harmful to both marine life and humans. Herein, a pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) technique for the detection of microplastics in aquatic shellfish is demonstrated. The organic matter in aquatic shellfish was removed by alkali digestion. Subsequently, using hexafluoroisopropanol as the extraction solvent, the extraction method was optimized. The influence of the digestion process on the nature of microplastics was investigated by analyzing the samples before and after the alkali treatment via infrared spectrometry, laser particle sizing, and scanning electron microscopy. Spiked recovery experiments and an analysis of actual samples were performed using PA6 and PA66 as analytes. A quantitative analysis of the characteristic ion fragment produced by high-temperature cracking was performed after chromatographic separation and mass spectrometry identification. The linear range of this method for PA6 and PA66 was 2–64 μg. The limits of detection of PA6 and PA66 were 0.2 and 0.6 μg, while the limits of quantitation were 0.6 and 2.0 μg, respectively. Recovery ranged from 74.4 to 101.62%, with a precision of 4.53–7.56%. The results suggest that the Py-GC/MS technique is suitable for the analysis and detection of trace microplastics in aquatic shellfish.Keywords:microplastics;alkali digestion;pyrolysis–gas chromatography–mass spectrometry;aquatic shellfish;nylon

High-Strength GO/PA66 Nanocomposite Fibers via In Situ Precipitation and Polymerization

Ao Gu,Jian Wu,Liming Shen,Xiaoyan Zhang,Ningzhong Bao

The uniform dispersion of graphene oxide (GO) and strong interfacial bonding are the key factors in achieving the high mechanical strength of GO/polymer composites. It is still challenging to prepare GO/PA66 composites with uniform GO dispersion by the in situ polymerization method. In this paper, we prepare GO/PA66 salt nanocomposite by in situ precipitating PA66 salt with GO in ethanol. The GO/PA66 nanocomposite fibers are then fabricated using the as-prepared GO/PA66 salt by in situ polymerizing and melt spinning. By tuning the GO content, the tensile strength and Young’s modulus of the GO/PA66 fibers are increased from 265 ± 18 to 710 ± 14 MPa (containing 0.3 wt% GO) and from 1.1 ± 0.08 to 3.8 ± 0.19 GPa (containing 0.5 wt% GO), respectively. The remarkable improvements are attributed to the uniform dispersion of GO in the GO/PA66 salt nanocomposite via ionic bonding and hydrogen bonding in the in situ precipitation process, and the covalent interfacial bonding between the GO and PA66 during the in situ polymerization process. This work sheds light on the easy fabrication of high-performance PA66-based nanocomposites.Keywords:Polyamide 66;GO;in situ precipitation;dispersion;mechanical properties

Functional-group-mediated interfacial engineering of BF/PA66 composites for enhanced interfacial adhesion

Fuhao Liu,Shifa Su,Zhenhua Wang,Shanhu Niu,Dawei Li,Na Zhang,Chuanhui Gao

To meet the demand for lightweight, high-performance and green sustainable materials, basalt fiber-reinforced polyamide 66 (BF/PA66) composites show great application potential in aerospace and automobile manufacturing. However, poor interfacial compatibility between basalt fibers (BF) and PA66 matrix limits their comprehensive performance. In this study, BF surfaces were modified with amino (KH-550), epoxy (KH-560) and mercapto (KH-590) silane coupling agents to enhance interfacial bonding. Systematic tests were conducted on composites with 15 wt% fiber content. The results showed that all silane coupling agents were successfully grafted onto BF surfaces via Si-O-Si covalent bonds, improving fiber surface roughness and reactivity. KH-550 modification achieved the optimal performance: tensile, flexural and impact strengths increased by 25.12%, 45.57% and 46.08% respectively compared with pure PA66, with the strongest interfacial binding energy (−7.84 kcal/mol). Additionally, KH-550 reduced water absorption by 38.89% and improved thermal stability. This study provides an efficient and eco-friendly method for interfacial regulation of BF/PA66 composites.

High self-extinguishing and thermal insulating PA66 composites enhanced with flame-retardant cellulose nanocrystals

Qinan Hou,Yunhui Chen,Jiefei Wang,Meiqin Wu,Hou-Yong Yu,Xiaohua Wang

Polyamide 66 (PA66), a globally attractive high-performance plastic, is hindered by its poor fire resistance, which triggers excessive smoke and dripping. In this work, we introduce a novel halogen-free, thermal insulating flame-retardant for PA66, modified by cellulose nanocrystals (CNCs) with 3-aminopropyltriethoxysilane (APTES) and phosphoric acid (PA) to form a spider web-like nano composite CNC/A/P, by improving the thermal stability and inhibiting the droplet phenomenon of PA66. This high self-extinguishing flame retardant owns a 56.9 % residual carbon rate and the limiting oxygen index of 42.74 %. PA66-C15, incorporating 15 wt% CNC/A/P, significantly enhances PA66's flame retardancy, achieving a V-0 rating, and a rising LOI of 46.7 % from 21.6 %. Surprisingly, a 114.3 % temperature reduction (194.1 °C) under heating alcohol lamp were also observed in this PA66 composite, preserving superior tensile strength mechanical properties and thermal insulation. This study presents a promising, high-performance CNC-based flame-retardant material with excellent fire retardancy and mechanical properties.

Chain Length Regulation of PA66/PPO-PEO-PPO Multiblock Elastomers: Synthesis, Structure, and Property

Chenglong Wan,Like Hou,Qing Hu,Zihe Zhao,Yanxia Yang,Biao Zhao,Jianping Deng,Kai Pan

A series of thermoplastic polyamide elastomers (TPAEs) utilizing polyamide 66 (PA66) as the hard segment and amorphous diamine-sealed poly(oxypropylene)-poly(oxyethylene)-poly(oxypropylene) (PPO-PEO-PPO) with different molecular weight as the soft segment are synthesized through one-step melt polycondensation method. The chemical structure of TPAEs is confirmed by Fourier transform infrared spectroscopy (FT-IR) and hydrogen magnetic resonance spectroscopy ( 1 H-NMR). Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) results show that short-chain polyetheramine (Jeffamine-ED600) has good compatibility with PA66, which limits crystal growth and greatly reduced crystallinity, can be used as diluent to reduce the melting point of the material. However, the microphase separation of long-chain polyetheramine (Jeffamine-ED900) and PA66 leads to the increase of crystallinity, and the melting temperature does not decrease significantly with the increase of soft segment content. Mechanical properties tests show that all TPAEs exhibit good mechanical properties and excellent energy dissipation, with tensile strength up to 45 MPa and elongation at break up to 630%. The introduction of PEO unit results in the water absorption of TPAEs ranging from 25 to 65%, and the surface resistivity varying between 2.45 × 10⁹ and 1.6 × 10¹⁰ Ω, suggesting the synthesized TPAEs are suitable for use as permanent anti-static materials.

A PA66 lamellar crystal film with excellent triboelectric performance in vertical contact separation mode

Jincheng Liu,Po Ji,Zixun Wang,Xianglan Liu,Yongxing Lin,Xiangyang Li,Lin Chen,Xingyou Tian,Sihai Luo

Triboelectric nanogenerators (TENGs) are gaining tremendous attention as an environmentally friendly technology that converts low-frequency mechanical energy into electrical energy. However, the output of TENGs is limited by the tribolayer material used. In this study, a unique lamellar crystal triboelectric nanogenerator (LC-TENG) that uses polyamide-66 (PA66) lamellar crystal spin-coated films as positive triboelectric layers and FEP films as negative triboelectric layers is presented. The large vertical interlocking nanosheet structure on the PA66 spin-coating film, incubated in solution, improves surface roughness and promotes charge storage capacity. Under a constant force of 10 N and a frequency of 2 Hz, the LC-TENG with dimensions of 3 cm × 3 cm can achieve a peak voltage and current of 153 V and 7.35 μA, respectively. With an external load resistance of ∼11 MΩ, the TENG's maximum power density is 0.67 W m−2. The LC-TENG can easily harvest energy from human motions and light up a 36-LED array driven by a linear motor. Compared to TENGs using the initial smooth spin-coated film as the triboelectric electrode, the voltage and current from the lamellar structure film are 2.38 times and 2.17 times higher, respectively. This is the first time that a lamellar crystal structure has been introduced into friction material optimization, providing an efficient and feasible way to explore active sensor or electrode materials for self-powered electronic devices.

Bioactivity–Structure Synergy for Osteogenesis: An Alpha-Ketoglutarate-Releasing PA66/HAp/Gelatin Gradient Porous Scaffold

Siluo Dai,Jiaxin Hu,Yiran Li,Tingting Ma,Aolong Li,Zhengyang Qin,Yubao Li,Jidong Li

Three-dimensional printed porous scaffolds provide the necessary mechanical support for bone repair. However, their inherent structural design often leads to insufficient cell attachment sites within the large pores, resulting in a low-density and uneven spatial distribution of initially adhered cells, which ultimately hampers bone regeneration. To address this limitation, we developed a gradient-functionalized scaffold by incorporating an α-ketoglutarate (AKG)-loaded gelatin (Gel/AKG) network into the macropores of a 3D-printed polyamide 66/hydroxyapatite (PH) composite scaffold. This design aims to facilitate initial cell adhesion and subsequent osteogenic differentiation. Material optimization confirmed that a formulation of 5 wt % gelatin carrying 0.25 wt % AKG achieved optimal perfusion and structural stability within the scaffold. This construct establishes an integrated microporous network that significantly enhances surface properties, actively guiding and promoting dense early cell colonization. The degradation of gelatin timely creates space for bone ingrowth, while the sustained release of AKG continuously enhances cell osteogenic activity. In vivo animal studies further revealed an 110% increase in new bone volume in the experimental group compared to the control after 8 weeks implantation. In conclusion, this strategy successfully integrates robust mechanical support, guided cell adhesion, and bioactive regulation into a spatiotemporally coordinated system, offering a promising solution for bone defect repair by harmonizing structural compatibility with functional regeneration.

3D-printed nHA/PA66 porous scaffold: Regulating immune balance and vascularization synergistically promotes bone regeneration

Caiping Yan,Fukang Zhu,Hao Liang,Changxing Liu,Bin He,Taiyou Wang,Heling Tan,Hong Li,Dianming Jiang,Bo Qiao

3D-printed porous scaffolds have emerged as a potential solution for treating critical-sized bone defects, yet localized inflammatory imbalance leads to suboptimal therapeutic outcomes. This study utilized nHA/PA66 composite material as the foundation, employing APF additive manufacturing technology to fabricate a three-dimensional porous scaffold (HP) suitable for local bone filling, and functionalized the porous scaffold through modification with polydopamine and magnesium ions (Mg 2+ ) (HPDM). First, the physicochemical properties and biosafety of the HPDM scaffold were verified, followed by a comparative analysis of its effects on macrophage phenotype transformation, vascular endothelial cell differentiation, and pre-osteoblast differentiation differences. The HPDM scaffold achieves coordinated balance in the transformation between M1 and M2 macrophages through sustained release of polydopamine and Mg 2+ . Mg 2+ plays a crucial role in inflammatory regulation by downregulating the NF-κB signaling pathway. Furthermore, several experiments demonstrated that the HPDM scaffold regulates orderly inflammatory responses to promote intercellular interactions, stimulating angiogenesis and osteogenic regeneration. In New Zealand rabbits' femoral condyle bone defect model, the HPDM porous scaffold achieved significant vascularized bone regeneration. This study confirms that the functionalized HPDM porous scaffold prepared using nHA/PA66 as the base material has significant potential in regulating immune responses and enhancing vascularized bone regeneration.

Modified n-HA/PA66 scaffolds with chitosan coating for bone tissue engineering: cell stimulation and drug release

Qin Zou,Junfeng Li,Lulu Niu,Yi Zuo,Jidong Li,Yubao Li

Poly(arylene ether nitrile ketone) Resin-Modified PA66 Filaments for FFF Printing: Mechanical Reinforcement and Improved Printability

Chenglong Wang,Jianhua Han,Lishuai Zong,Xigao Jian,Jinyan Wang

Polyamide 66 (PA66) is a widely used engineering plastic, which is applied in diverse fields due to its high mechanical strength, excellent wear resistance, and outstanding chemical stability. However, in fused filament fabrication (FFF) 3D printing, PA66 suffers from two critical challenges that restrict its printability and applications: low melt viscosity leads to reduced printing precision and difficulties in filament fabrication, while significant crystalline shrinkage during cooling causes warpage. Herein, an amorphous poly(arylene ether nitrile ketone) resin (PPHENKK) with a glass transition temperature of 225 °C (below the melting point of PA66) and a high melt viscosity is synthesized, and polyethyleneimine (PEI) is subsequently incorporated as a compatibilizer. The crystallinity of the PA66/PPHENKK/PEI blend decreased by 27%, and the coefficient of thermal expansion was reduced by 20%, enabling the successful preparation of filaments suitable for FFF 3D printing with high dimensional accuracy and negligible warpage. Furthermore, with the introduction of PPHENKK, the tensile strength reaches 62.6 MPa (an increase of 25.5%), while the elongation at break remains at a relatively high level of 13.1%. Meanwhile, the heat resistance was improved, with the glass transition temperature increased by 11 °C. Overall, the developed PPHENKK/PA66 blend exhibits a balanced combination of mechanical strength, thermal stability, and dimensional accuracy, making it an effective material for advanced FFF 3D printing applications.