Nylon 6 Research Articles

Evonik pushes ahead on nylon 12 plant

Evonik pushes ahead on nylon 12 plant

Evonik makes progress on nylon 12 plant

Evonik makes progress on nylon 12 plant

Processing and mechanical performances of ZrO2 reinforced thermoplastic Nylon 6 composites for gear applications

In this paper, the impacts of including Zirconium Oxide (ZrO2) on the mechanical properties of Nylon 6 (N6) based composites were researched. N6 was fortified with ZrO2 by fluctuating the weight extents. The test examples for mechanical and tests were shaped in an injection moulding machine. The mechanical properties of N6, ZrO2 fortified N6 polymer composites were researched as far as malleable, flexural, effect and hardness tests. The N6 composite containing 10 wt% ZrO2 uncovered the better mechanical practices. Checking electron microscopy (SEM) was used to analyze the break surfaces microstructure of malleable test. The expansion of ZrO2 upgrades the existence state of ordinary N6 positively. Additionally, this composite displays more grounded interfacial holding qualities with improved mechanical attributes.

Dual nanofiber scaffolds composed of polyurethane- gelatin/nylon 6- gelatin for bone tissue engineering

The aim of the present study was to develop a fibrous scaffold with unique physiochemical, mechanical and biocompatible characteristics with morphological structure similar to the native extracellular matrix (ECM). A dual non-woven ultrafine fibrous scaffold composed of polyurethane (PU)/Nylon 6 (N6) hybrid polymers mixed with natural gelatin (Gel) was fabricated by a dual syringe electrospinning technique. Pronounced dual composite fine fibers of PU/N6 (148 ± 43 nm) and (PU-Gel)/(N6-Gel) (161 ± 79 nm) with an interconnected porosity were obtained. The dual N6/Pu fibrous scaffold showed higher tensile strength and tensile modulus than a dual PU-Gel/N6-Gel scaffold, whereas the dual composite fibrous scaffold containing Gel induced the largest elongation at breaking load. Biomimetic mineralization characteristics observed at different time intervals showed the formation of a bone apatite like layer on the dual composite fibrous scaffold, indicating good bioactivity. The dual (PU-Gel)/(N6-Gel) nanofibers composite fibrous scaffold had better wettability compared to the other scaffolds, and supported high osteoblast cell proliferation. This suggests that the fabricated dual composite fibrous scaffolds containing gelatin may have the potential to be applied in bone tissue engineering.

Lysozyme/collagen multilayers layer-by-layer deposited nanofibers with enhanced biocompatibility and antibacterial activity.

Biological meshes have always posed a challenge in biological medicine, for which nanocomposites with enhanced biocompatibility and antibacterial activity may be beneficial. In this study, lysozyme (LY) and collagen (Col) were alternately deposited on silk fibroin (SF) and nylon 6 (N6) composite nanofibrous mats using a layer-by-layer (LBL) self-assembly technique. The mechanical properties, biocompatibility, and antibacterial activity of the LBL structured mats were characterized systematically to investigate the impact of the LBL process on the biological properties of SF/N6 nanofibrous mats. Our results showed that the effective deposition of LY and Col may affect the surface topography, mechanical properties, and wetting behavior of the SF/N6 nanofibrous mats. Moreover, LBL structured mats exhibited excellent biocompatibility and antibacterial properties. Among all the tested mats, those coated with 10 bilayers of LY and Col displayed the best biocompatibility, and relatively good mechanical and antibacterial properties. Thus, LBL structured mats, especially those with a 10 bilayer coating, are potentially valuable in clinical therapy for pelvic organ prolapse in the future.

Effect of lung protective ventilation on perioperative pulmonary infection in elderly patients with mild to moderate COPD under general anesthesia

ObjectiveThe research aims to explore the effects of different ventilation time on postoperative pulmonary infection in elderly patients with the mild and moderate chronic pulmonary obstructive disease (COPD), so as to provide evidence for reducing postoperative pulmonary infection complications in patients with COPD. Methods120 elderly patients with mild and moderate COPD were selected as the research objects. First, the general information of patients with COPD before surgery and the difference between healthy population and lung forced expiratory volume in 1s (FEV1), forced vital capacity (FVC), FEV1/FVC and maximum midexpiratory flow (MMEF) functional indexes were analyzed and detected. Patients with COPD were operated on with single lung ventilation and general anesthesia. Patients with mild and moderate COPD were divided into two groups according to lung ventilation time (ventilation time 1.0–2.0h group, ventilation time >2.0h group). The inflammatory factors of IL-6, IL-21, TNF-α, and CXCL13 as well as inflammatory indicators of polycaprolactam (PCT), C-reactive protein (CRP) and white blood cell (WBC) in serum of all patients were detected after the operation. The probability of pulmonary infection after COPD was diagnosed and analyzed. Finally, the regression analysis of postoperative pulmonary infection in COPD patients was analyzed. Results(1) The results showed that the smoking rate of mild and COPD patients was significantly higher than that of healthy people (P<0.05). (2) The lung function indexes of the mild and moderate groups were significantly lower than those of the control group (P<0.01), while the lung function indexes of the moderate group were significantly lower than those of the mild group (P<0.05). (3) All the inflammatory indicators of moderate COPD patients were significantly higher than those of mild COPD patients (P<0.05). (4) All inflammation-related indicators in patients with mild and moderate COPD with ventilation time of >2.0h were significantly higher than those in the 1.0–2.0h group (P<0.05). (5) The probability of postoperative pulmonary infection in moderate patients was significantly higher than that in mild patients (P<0.01). The probability of postoperative pulmonary infection in >2.0h group was significantly higher than that in the 1.0–2.0h group (P<0.01). (6) Multivariate Logistic regression analysis results showed that lung function, duration of lung ventilation and smoking were independent risk factors for postoperative pulmonary infection in COPD patients. ConclusionIt is important to detect pulmonary function before surgery, maintain single lung ventilation protection for no more than 2.0h during surgery, and quit smoking to improve pulmonary infection in patients with COPD after surgery. In addition, the incidence of postoperative pulmonary infection in patients with moderate COPD was higher than that in patients with mild COPD, suggesting that early treatment in patients with COPD was also of great significance in reducing the incidence of postoperative pulmonary infection.

Biomimetic Nylon 6-Baghdadite Nanocomposite Scaffold for Bone Tissue Engineering.

Nature creates soft and hard ingredients revealing outstanding properties by adjusting the ordered assembly of simple primarily components from the nano- to the macro-scale. To simulate the important features of native tissue architecture, wide researches are being performed to develop new biomimetic custom-made composite scaffolds for tissue engineering. Here, we introduced a three-dimensional (3D) biomimetic scaffold based on the cuttlefish bone (CB) as a sacrificial template for bone tissue engineering. By combination of nylon 6 (N6), various amounts of baghdadite (BG) nanopowder and sacrificial template CB, a novel nanocomposite scaffolds was successfully developed with hierarchical microstructure and open pores in the range size in long and minor axis of 153-253μm and 39-70μm, respectively, depending on the BG content. In addition, incorporation of BG improved the mechanical properties of the scaffolds. Noticeably, the compressive strength and compressive modulus enhanced from 0.47±0.05 to 1.41±0.25MPa and from 3.16±0.14 to 6.23±0.3MPa, respectively. Moreover, results demonstrated that the incorporation of BG nanoparticles in the N6 matrix significantly improved bioactivity in simulated body fluid and increased degradation rate of N6 scaffold. Additionally, 3D nanocomposite scaffolds disclosed meaningfully excellent cellular responses. It is envisioned that the provided N6-BG nanocomposite scaffold might be a promising candidate for bone tissue engineering applications.

Interaction study between M-Phenylenediamine, Trimesoyl Chloride and Nylon 66 using Molecular Dynamic Simulation

The thin film composite (TFC) membrane is a porous membrane layered by a polyamide active layer. In the experimental work, the polyamide active layer prepared by the interaction between monomers, m-phenylenediamine (MPD) and trimesoyl chloride (TMC) which deposited on a membrane support. Considering the possibility of producing a loose TFC membrane and affect the separation performance, this study enlightens the interaction between monomers with Nylon 6 6 (N66) support membrane using simulation - molecular dynamic (MD). Different simulation system has been investigated with varying the ratio molecule of MPD to TMC where, TFC1 (1:1), TFC2 (3:1) and TFC3 (3:2) to the tertiary system of N66/MPD/TMC. The simulation was set for a COMPASS force field, where the equilibrium phases in a microcanonical (constant volumes and total energy) (NVE) followed by run-production stage (constant pressure and temperature ensembles) (NPT) ensembles. The temperature and pressure were set at 323.15 K and 1atm respectively. The polyamide TFC was found to be formed by the main interactions between nitrogen (N) from MPD group to the carbon, (C) from TMC main chain at ranges of 4.25Å. Overall interaction can be observed between N from TFC layer with O atom from the substrate layer. All of the intermolecular interactions take place at 3.25Å distance. The best interaction in N66 to MPD and TMC system to the weakest is in the arrangement of TFC2 > TFC3 > TFC1. The highest intensity was obtained by the TFC2, indicating the best ratio of 3:1 of MPD molecules to TMC molecule with support polymer when fully polymerized occurred. This study suggests that ratio N66 to MPD and TMC in TFC2 is the best to interaction between TFC layer and substrate for fabrication of the TFC membrane.

Production of Nylon-6/Cellulose Nanocrystal Composite Films Using Solvent Dissolution

Nylon-6 (N6) composites were incorporated with cellulose nanocrystals (CNCs) extracted from sugarcane bagasse via solvent dissolution. The effect of the CNC content was estimated at 0, 1, 3, 5 and 7 wt%. Atomic force microscopy images showed that the diameter and length of the obtained CNCs were 52.4 ± 14.8 and 400.38 ± 104.8 nm, respectively. Fourier transform infrared analysis illustrated the increasing dominant peak intensity of cellulose in the composites with a higher CNC content. X-ray diffraction and mechanical analysis determined the optimum improvement in crystallinity index and Young’s modulus in loading 1 wt% of CNCs, with values of 64.37 ± 0.12% and 675.27 MPa, respectively. The highest opacity value of the N6/CNC composites was 8.592 ± 0.062 for N6/CNC-7%. Moreover, CNCs decreased the thermal property of the N6 composites. These results suggested that CNCs have great potential to reinforce N6 polymers.

Extracellular Oxygen Sensors Based on PtTFPP and Four-Arm Block Copolymers

Three four-arm amphiphilic block copolymers with different chain lengths, consisting of a hydrophilic chain of polyethylene glycol (PEG) and hydrophobic segment of polycaprolactam (PCL), were synthesized and used to encapsulate the high-efficient and hydrophobic oxygen probe of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) to form polymer micelles. This approach enabled the use of PtTFPP in aqueous solution for biosensing. Experimental results demonstrated that the particle sizes of these nano-oxygen sensors between 40.0 and 203.8 nm depend on the structures of block copolymers. PtTFPP in these micelles showed an effective quantum yield under nitrogen environment, ranging from 0.06 to 0.159. The new sensors are suitable for analyzing dissolved oxygen concentrations in the range of 0.04–39.3 mg/L by using the linear Stern–Volmer equation at room temperature. In addition, it has been shown that these sensors are capable of in situ monitoring the dissolved oxygens in the culture medium of E. coli and Romas cells during the respiration process, and distinguishing the drug activity of antibiotic ampicillin from that of antimycin A. This study showed that the use of these nanostructured multi-arm block copolymer micelles can achieve efficient biological applications without specific structural modification of the hydrophobic PtTFPP probe, which is expected to have broad prospects.

Study on the Thermal Decomposition of Plastic Residues

The use of plastics in the last decades significantly increased, thus plastic recycling processes are needed. Generally, mixtures of plastic materials are disposed together, hence the recovery of the polymeric material is difficult and expensive. Plastic residues could be valorized by thermal degradation processes aimed at recovering energy and/or valuable compounds for chemical industry. The main technologies used for this purpose are gasification and pyrolysis. The latter is a thermal degradation process that occurs in the absence of oxygen at moderate temperature (300-700°C), that could be used to recover the thermal power of biomasses. The reaction products are bio-oil, biogas and biochar. The aim of this work was to employ pyrolysis to energetically exploit different pure plastic materials, namely polyethylene terephthalate (PET), polyamide (Nylon-6), polyvinyl chloride (PVC) and polyurethane (PU), as well as a complex one such as end of life tyres (ELT). The reaction was performed at 400 °C for 90 min. The pyrolysis system was composed by a tubular quartz reactor heated with a tubular vertical oven. An integrated condenser was used to separate the liquid reaction products, while the incondensable gases were collected in a latex balloon. The reaction products were quantified gravimetrically and, in order to evaluate the functional groups, characterized by FTIR analysis. The reaction gases were also analyzed by GC-MS to determine the composition of this fraction. Results obtained from the different plastics were significantly different in terms of distribution and composition. In particular, PET produced a biogas consisting mainly of acetaldehyde and hydrocarbons, while the liquid fraction was composed of benzoic and terephthalic acids. Nylon-6 degraded producing a large amount of reaction gas (65 g/100g) composed of ammonia and light hydrocarbons, while the reaction liquid was mainly caprolactam. Around 53 g/100g of PVC reaction products were gaseous, mainly hydrochloric acid, followed by toluene and benzene at high concentrations. The degradation of PU produced a reaction gas, mainly composed by formic and acetic aldehydes. ELT pyrolysis was responsible for the production of high amounts of solid residue, while reaction gas and liquid seemed to be mainly constituted by hydrocarbons. In general, the study of pure plastic pyrolysis could help to better understand the thermal decomposition of complex plastic residues such as ELT.

LBL deposition of chitosan and silk fibroin on nanofibers for improving physical and biological performance of patches.

Pelvic floor dysfunction diseases (PFD) become more prevalent with the increase of elderly population, and complications of pelvic floor reconstructive surgery (e.g. infection and exposure of mesh) have been troubling to patients and gynecologists. In this study, the nanofibrous mats were prepared by alternately depositing chitosan (CS) and silk fibroin (SF) on Nylon6 (N6) nanofibrous mats via layer-by-layer (LBL) technique. The as-prepared mats were characterized. The results showed that CS and SF molecules were successfully assembled on the nanofibers. Additionally, after LBL modification, the hydrophilicity of the nanofibrous mats was reduced and the mechanical properties were improved. Furthermore, the antibacterial activity of the LBL-structured mats reached >95% inhibiting Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The in vitro cell co-culture experiments indicated that LBL-structured mats had smaller toxic effects and more excellent biocompatibility to L929 fibroblasts, especially the mats with 15 bilayers coated films. Hence, the LBL-structured mats are promising materials for pelvic floor reconstruction to reduce postoperative pelvic complication rates.

Dyeing of Nylon 66 Woven Fabric Using Bromophenol Blue and Color Change in Acidic Solution

Dyeing of Nylon 66 Woven Fabric Using Bromophenol Blue and Color Change in Acidic Solution

Design of antimicrobial polycaprolactam nanocomposite by immobilizing subtilisin conjugated Au/Ag core-shell nanoparticles for biomedical applications

Preparation of the gold core and silver shell NP (AuAgNP) is challenging because of the facile oxidation of silver. Here such a NP is carefully synthesized and conjugated with subtilisin to arrive at a stable spherical material of 120–130 nm in diameter (AuAgSNP). A biomaterial prepared by immobilizing AuAgSNP on polycaprolactam (PCL) exhibits antibiofilm properties against S. aureus and E. coli, but with lesser potency than the one prepared with bare AuAgNP. Subtilisin degrades the adhesive surface proteins of the bacteria thereby preventing the biofilm formation. Subtilisin conjugated AuAgSNP is not cytotoxic to 3T3 cells at its MIC, in contrast to AuAgNP. The presence of subtilisin promotes the fibroblast proliferation. This study indicates that AuAgSNP has antibacterial/antibiofilm activities as well as biocompatibility unlike NPs which are very cytotoxic to cells. Hence AuAgSNP can be used in medical implants and devices.

Fabrication of Air Freshening Spongy Three Dimensional Electrospun Membrane

In this work, air freshening spongey 3D nanofibrous membrane of nylon-6 (N6) is fabricated via electrospinning process. Viscous N6 solution dissolved in formic acid/acetic acid solvent system was allowed for electrospinning to obtain 2D membrane. As-fabricated 2D membrane is converted into 3D one by using gas foaming technique. Lemon grass essential oil as a fragrance was incorporated through 2D and 3D porous membrane by evaporating essential oil at 60°C for 5 hours. The morphology of different membranes was examined from FE-SEM images which showed that 3D membrane is far porous than 2D one. The control fragrance release from the 3D spongy membrane was evaluated from the weight loss of oil-loaded membrane for 60 days which showed that the 3D membrane had more oil uptake and the controlled release of oil over the studied time. FT-IR spectra of oil-incorporated 3D membrane at different interval of times indicated the presence of fragrance even after the 60 days. The result showed that as-fabricated sponge 3D membrane may be a potential candidate for the future air freshening materials.Journal of the Institute of Engineering, 2018, 14(1): 14-21

Selection and experimental evaluation of shaking rods of canopy shaker to reduce tree damage for citrus mechanical harvesting

Canopy shaking system is one of the research hotspots for large-scale mechanized fruits harvesting. Shaking rods considered as one of the essential components of canopy shaker are responsible for transferring mechanical energy from shaking mechanism to different regions of tree canopy. This transfer depends on the characteristics of the shaking rods that directly strike the tree canopy. In order to evaluate the effects of the shaking rods on tree damage level and fruit removal percentage, three kinds of shaking rods with different materials or shapes were selected. Based on the results of bending deformation tests, it was proven that the rigid shaking rod (R1) with the material of Polyvinyl Chloride (PVC) did more resistance against producing bending deformation in comparison with the other two types of shaking rods with the material of Polyamide Nylon 12 (PA). By contrast, the position close to the free end of the flexible shaking rod was easier to be deformed by less external force. In addition, dynamic analysis and vibration performance tests indicated that the rigid shaking rod could produce stronger vibration with higher shaking frequency of 4.8 Hz and maximum acceleration of 31.4 m/s2. Finally, the results of field trials indicated that the flexible bow-shaped shaking rod (R3) has a better widespread performance to achieve comparative higher fruit removal percentage up to 82.6% while producing lower tree damage rate of 5.36%. This study demonstrates that the materials or shapes of the shaking rod could significantly influence the fruit detachment rate and tree damage level. This study would provide an essential reference for the application of shaking rods for canopy shaker. Keywords: citrus harvester, shaking rod, canopy shaker, bending deformation, tree damage, fruit removal DOI: 10.25165/j.ijabe.20181102.4126 Citation: Pu Y J, Toudeshki A, Ehsani R, Yang F Z, Abdulridha J. Selection and experimental evaluation of shaking rods of canopy shaker to reduce tree damage for citrus mechanical harvesting. Int J Agric & Biol Eng, 2018; 11(2): 48–54.

Bioinspired Aryldiazonium Carbohydrate Coatings: Reduced Adhesion of Foulants at Polymer and Stainless Steel Surfaces in a Marine Environment

Surface treatments that minimize biofouling in marine environments are of interest for a variety of applications such as environmental monitoring and aquaculture. We report on the effect of saccharide coatings on biomass accumulation at the surface of three materials that find applications in marine settings: stainless steel 316 (SS316), Nylon-6 (N-6), and poly(ether sulfone) (PES). Saccharides were immobilized via aryldiazonium chemistry; SS316 and N-6 samples were subjected to oxidative surface pretreatments prior to saccharide immobilization, whereas PES was modified via direct reaction of pristine surfaces with the aryldiazonium cations. Functionalization was confirmed by a combination of X-ray photoelectron spectroscopy, contact angle experiments, and fluorescence imaging of lectin–saccharide binding. Saccharide immobilization was found to increase surface hydrophilicity of all materials tested, while laboratory tests demonstrate that the saccharide coating results in reduced protein adsorption in th...

Preventive effect of endoclip and endoloop on post-polypectomy bleeding of large colorectal polyps and literature review

Objective To investigate the preventive effect of endoclips and endoloops on post-polypectomy bleeding of large colorectal polyps. Methods Data of patients, who underwent polypectomy during January 2013 to March 2016, were retrospectively collected. The diameters of all polyps were more than 10 mm. Cases were divided into 4 groups. Before large pedunculated (with thick stalks) polyps were resected, endoclips were used to ligate the pedicles of polyps in Group A, and endoloops were used in Group B. After large sessile and pedunculated (without thick stalks) polyps were resected, endoclips were used to close the incision of polypectomy in Group C, but not in Group D. The immediate and delayed post-polypectomy bleeding rate and clinicopathologic features were studied. Articles about endoclip or endoloop on preventing post-polypectomy bleeding in PubMed in last five years were searched and analyzed. Results A total of 2 006 polyps were included. The immediate bleeding rate was 3.4% (5/147) and 3.8% (5/132) of Group A and B, respectively. The delayed bleeding rate was 6.1% (9/147) and 7.6% (10/132) of Group A and B, respectively. The delayed bleeding rate of Group C and D was 3.2% (28/888) and 1.9%(16/839), respectively. None of the bleeding cases needed a surgical operation. And no perforation occurred. Six articles were included for analysis. Most of articles revealed that endoclip and endoloop were effective tools in prevention of post-polypectomy bleeding. Conclusion Endoclips and endoloops are useful to prevent bleeding after resection of large pedunculated (with thick stalks) polyps. For large sessile and pedunculated (without thick stalks) polyps (diameter>10 mm), the effect of endoclips to prevent post-polypectomy bleeding still needs further discussion. Key words: Intestinal polyps; Hemorrhage; Endoscopes; Nylons; Titanium

Adhesion of blended polymer films

In this work, the adhesion energies of two dissimilar polymer films after thermal bonding are studied. The films were formed from the emulsions of polycaprolactone (PCL) and nylon-6 (N6) spin-coated onto metal substrates. After that, the solidified blend polymer films on the metal substrates were faced with additional PCL films on metal substrates and thermally bonded to them. The surface structure of blend films was elucidated prior to thermal bonding by staining them using Rhodamine B. The dye stained only N6 leaving PCL undyed and the exposed structure was analyzed using digital photography, which revealed the surface concentration of PCL, as well as the N6 and PCL distributions over the surfaces. It was discovered that PCL-N6 domains would remain partially mixed, influencing the adhesion energy measured.

Effect of Nanoclay on Thermomechanical Behaviour of Graphene Oxide/Polymer Composites

This work explores the effectiveness of nanoclay (NC) as compatibilizer in graphene oxide (GO) reinforced Nylon66 (N66) nanocomposites, prepared through melt mixing technique. Different composites have been prepared with varying concentration of NC to determine its optimum content for an effective improvement in thermomechanical properties of GO/N66 composites. XRD curves have shown that properly exfoliated nanocomposites have been synthesized with the use of NC as secondary filler. FTIR has been used to confirm presence of different elements and the nature of interaction between N66 and fillers. Thermogravimetric analysis have shown that the effect of GO and NC on thermal decomposition behaviour of GO/N66 composites is insignificant. The mechanical and thermomechanical properties of these composites have been studied with the help of tensile tests, flexural tests and dynamic mechanical analysis. The incorporation of 2 wt% NC in GO-N66 nanocomposite shows most significant improvement in its tensile and flexural strength (93.2% and 121.5%, respectively). DMA studies revealed improvement in storage modulus of GO-NC reinforced hybrid composites. Glass transition (Tg) of 2NC-GO-N66 nanocomposite have been noticed to improve by 12.5%. FESEM images have shown that agglomeration of nanoparticles takes place when the content of NC reaches 3 wt%. This provides the reason for poor mechanical and thermomechanical properties of the composite having NC more than 2 wt%.