Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Front Psychiatry ; 15: 1333528, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38525257

RESUMO

Background: Mental health has been found to be associated with risk of osteoarthritis (OA), but the causal relationship was not fully clarified. Methods: Two-sample Mendelian randomization (MR) study was conducted to investigate the causal relationship between neuroticism (n = 329,821) and the two most frequently affected parts of osteoarthritis (OA) (knee OA: case/control =24,955/378,169; hip OA: case/control = 15,704/378,169) using large scale summary genome-wide association study (GWAS) data. Inverse variance weighted (IVW), weighted median, and MR-Egger were used to estimate the causal effects. Multiple sensitivity analyses were conducted to examine the robustness of the causal estimates. Multivariable MR analysis was used to estimate the direct effects of neuroticism on OA after accounting for the other OA risk factors. Two-step MR approach was employed to explore the potential mediators of the causal relationship. Results: Univariable MR analysis indicated that 1-SD increase in genetically predicted neuroticism score was associated with an increased risk of knee OA (IVW: OR, 1.17; 95% CI, 1.087-1.26; p = 2.72E-05) but not with hip OA. The causal effects remained significant after accounting for the effects of BMI, alcohol drinking, and vigorous physical activity but were attenuated with adjustment of smoking. Further mediation analysis revealed that smoking initiation mediated a significant proportion of the causal effects of neuroticism on knee OA (proportion of mediation effects in total effects: 22.3%; 95% CI, 5.9%-38.6%; p = 7.60E-03). Conclusions: Neuroticism has significant causal effects on knee OA risk. Smoking might partly mediate the causal relationship. Further studies were warranted to explore the underlying mechanisms and potential use of neuroticism management for OA treatment.

2.
Macromol Rapid Commun ; 45(10): e2400037, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38437164

RESUMO

Gas sensors based on conducting polymers offer great potential for high-performance room temperature applications due to their cost-effectiveness, high-sensitivity, and operational advantage. However, their current performance is limited by the deficiency of control in conventional polymerization methods, leading to poor crystallinity and inconsistent material properties. Here, the quasi-liquid layer (QLL) on the ice surface acts as a self-regulating nano-reactor for precise control of thermodynamics and kinetics in the polymerization, resulting in a 7.62 nm thick two-dimensional (2D) polyaniline (PANI) film matching the QLL thickness. The ultra-thin film optimizes the exposure of active sites, enhancing the detection of analyte gases at low concentrations. It is validated by fabricating a chemiresistive gas sensor with the 2D PANI film, demonstrating stable room-temperature detection of ammonia down to 10 ppt in ambient air with an impressive 10% response. This achievement represents the highest sensitivity among sensors of this kind while maintaining excellent selectivity and repeatability. Moreover, the QLL-controlled polymerization strategy offers an alternative route for precise control of the polymerization process for conducting polymers, enabling the creation of advanced materials with enhanced properties.


Assuntos
Compostos de Anilina , Polimerização , Polímeros , Compostos de Anilina/química , Polímeros/química , Polímeros/síntese química , Amônia/análise , Amônia/química
3.
Small ; 20(24): e2309130, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38247181

RESUMO

Various physical and chemical reaction processes occur in non-aqueous liquid systems, particularly in oil phase systems. Therefore, achieving efficient, accurate, controllable, and cost-effective movement and transfer of substances in the oil phase is crucial. Liquid-phase photothermal actuators (LPAs) are commonly used for material transport in liquid-phase systems due to their remote operability and precise control. However, existing LPAs typically rely on materials like hydrogels and flexible polymers, commonly unsuitable for non-aqueous liquids. Herein, a 3D porous poly(vinylidene fluoride) (PVDF)/Ti3C2Tx actuator is developed using a solvent displacement method. It demonstrates directional movement and controlled material transport in non-aqueous liquid systems. When subject to infrared light irradiation (2.0 W cm-2), the actuator achieves motion velocities of 7.3 and 6 mm s-1 vertically and horizontally, respectively. The actuator's controllable motion capability is primarily attributed to the foam's oil-wettable properties, 3D porous oil transport network, and the excellent photothermal conversion performance of Ti3C2Tx, facilitating thermal diffusion and the Marangoni effect. Apart from multidimensional directions, the actuator enables material delivery and obstacle avoidance by transporting and releasing target objects to a predetermined position. Hence, the developed controllable actuator offers a viable solution for effective motion control and material handling in non-aqueous liquid environments.

4.
Sci Total Environ ; 901: 165980, 2023 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-37543331

RESUMO

The design and production of materials with excellent mechanical properties and biodegradability face significant challenges. Poly (butylene terephthalate-co-caprolactone) copolyesters (PBTCL) is obtained by modifying the engineering plastic polybutylene terephthalate (PBT) with a simple one-pot process using readily biodegradable ε-caprolactone (ε-CL). The material has mechanical properties comparable to those of commercial biodegradable copolyester PBAT. Besides, this copolyester exhibited remarkable degradability in natural environments such as soil and ocean, for example, PBTCL1.91 lost >40 % of its weight after 6 months of immersion in the Bohai Sea. The effect and diversity of specific microorganisms acting on degradation in the ocean were analyzed by 16 s rDNA gene sequencing. Theoretical calculations such as Fukui function and DFT, and experimental studies on water-soluble intermediates and residual matrixes produced after degradation, confirmed that the insertion CL units not only act as active sites themselves susceptible to hydrolysis reactions, but also promote the reactivity of ester bonds between aromatic segments. This work provides insight for the development of novel materials with high performance and environmental degradability.

6.
J Hazard Mater ; 454: 131572, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37148790

RESUMO

Biodegradable plastics have emerged as a potential solution to the mounting plastic pollution crisis. However, current methods for evaluating the degradation of these plastics are limited in detecting structural changes rapidly and accurately, particularly for PBAT, which contains worrying benzene rings. Inspired by the fact that the aggregation of conjugated groups can endow polymers with intrinsic fluorescence, this work found that PBAT emits a bright blue-green fluoresces under UV irradiation. More importantly, we pioneered a degradation evaluation approach to track the degradation process of PBAT via fluorescence. A blue shift of fluorescence wavelength as the thickness and molecular weight of PBAT film decreased during degradation in an alkali solution was observed. Additionally, the fluorescence intensity of the degradation solution increased gradually as the degradation progressed, and was found to be exponentially correlated with the concentration of benzene ring-containing degradation products following filtration with the correlation coefficient is up to 0.999. This study proposes a promising new strategy for monitoring the degradation process with visualization and high sensitivity.

7.
Langmuir ; 39(12): 4530-4536, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36919933

RESUMO

Lossless and efficient robotic grasping is becoming increasingly important with the widespread application of intelligent robotics in warehouse transportation, human healthcare, and domestic services. However, current sensors for feedback of grasping behavior are greatly restricted by high manufacturing cost, large volume and mass, complex circuit, and signal crosstalk. To solve these problems, here, we prepare lightweight distance sensor-based reduced graphene oxide (rGO)/MXene-rGO coaxial microfibers with interface buffer to assist lossless grasping of a robotic manipulator. The as-fabricated distance microsensor exhibits a high sensitivity of 91.2 m-1 in the distance range of 50-300 µm, a fast response time of 116 ms, a high resolution of 5 µm, and good stability in 500 cycles. Furthermore, the high-performance and lightweight microsensor is installed on the robotic manipulator to reflect the grasp state by the displacement imposed on the sensor. By establishing the correlation between the microsensing signal and the grasp state, the safe, non-destructive, and effective grasp and release of the target can be achieved. The lightweight and high-powered distance sensor displays great application prospects in intelligent fetching, medical surgery, multi-spindle automatic machines, and cultural relics excavation.

8.
Molecules ; 28(4)2023 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-36838949

RESUMO

In this paper, an effective method for preparing poly (p-phenylene terephthalamide) -co- poly (dodecanedioyl) decylamine (PA10T/1012)/graphene oxide (GO) composites by pre-dispersion and one-step in situ polymerization was proposed for the first time. During the process of polycondensation, the condensation between the terminal amino groups of PA10T/1012 chains and the oxygen-containing functional groups of GO allowed nylon to be grafted onto graphene sheets. The effects of polymer grafting on the thermal and mechanical properties of (PA10T/1012)/GO composites were studied in detail. Due to the interaction between PA10T/1012 grafted graphene sheets and its matrix, GO is well dispersed in the PA10T/1012 matrix and physically entangled with it, forming a cross-linked network structure of polymer bridged graphene, thus obtaining enhanced tensile strength, tensile modulus and impact strength. More importantly, benefiting from the cross-linked network structure, the heat distortion temperature (HDT) of the composite is greatly increased from 77.3 °C to 144.2 °C. This in situ polycondensation method opens a new avenue to prepare polycondensate graphene-based composites with high strength and high heat distortion temperatures.


Assuntos
Grafite , Nylons , Temperatura , Polimerização , Grafite/química , Temperatura Alta , Polímeros/química
9.
J Hazard Mater ; 446: 130670, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36580787

RESUMO

The degradability improvement of poly(ethylene terephthalate) (PET), one of the most widely used but non-degradable disposable packaging material, is of great significance. However, the balance between degradability and mechanical properties remains a huge challenge. Herein, simple hydroxy acids, lactic acid (LA) and glycolic acid (GA) as easy hydrolysis sites were introduced into non-degradable PET via melt polycondensation. A series of high molecular weight poly(ethylene terephthalate-co-L­lactide) (PETL) and poly(ethylene terephthalate-co-glycolate) (PETG) copolyesters were synthesized with an excellent tensile strength greater than 50 MPa, much higher than that of most commercially available degradable polymers. The introduction of hydroxy acid endows PET with significantly improved composting and seawater degradation performance. Furtherly, the degradation rate of PETG with hydrophilic GA unit was faster than that of PETL, and the mineralization rate of PETG80 reaches 22.0%. The density of functional theory (DFT) calculation revealed that adding hydroxy acid to the PET molecular chain reduced the energy barrier of the hydrolysis reaction. The molecular polarity index (MPI) analysis furtherly confirmed that the higher affinity between the GA unit and water may be the primary reason for the faster degradation of PETG.

10.
Small ; 19(1): e2205071, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36366943

RESUMO

High-capacity electrochemical energy storage systems are more urgently needed than ever before with the rapid development of electric vehicles and the smart grid. The most efficient way to increase capacity is to develop electrode materials with low molecular weights. The low-cost metal halides are theoretically ideal cathode materials due to their advantages of high capacity and redox potential. However, their cubic structure and large energy barrier for deionization impede their rechargeability. Here, the reversibility of potassium halides, lithium halides, sodium halides, and zinc halides is achieved through decreasing their dimensionality by the strong π-cation interactions between metal cations and reduced graphene oxide (rGO). Especially, the energy densities of KI-, KBr-, and KCl-based materials are 722.2, 635.0, and 739.4 Wh kg-1 , respectively, which are higher than those of other cathode materials for potassium-ion batteries. In addition, the full-cell with 2D KI/rGO as cathode and graphite as anode demonstrates a lifespan of over 150 cycles with a considerable capacity retention of 57.5%. The metal halides-based electrode materials possess promising application prospects and are worthy of more in-depth researches.


Assuntos
Grafite , Compostos Inorgânicos , Metais , Potássio
11.
Ann Transl Med ; 10(22): 1244, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36544645

RESUMO

Background: Remimazolam tosylate is a new sedative combining the advantages of etomidate with remifentanil. Remimazolam tosylate shows effective in colonoscopy, but the optimal dose is not confirm. In this study, a single-center, prospective, randomized, double-blind, parallel trial were performed to compare the efficacy and safety of different doses of remimazolam tosylate for colonoscopy. Methods: Before colonoscopy, 120 recruited patients were randomized with a 1:1:1 ratio into 3 treatment groups: group A, 0.1 mg/kg remimazolam tosylate; group B, 0.15 mg/kg remimazolam tosylate; group C, 0.2 mg/kg remimazolam tosylate. Patients received 1 µg/kg fentanyl by intravenous injection over 30 s followed by the respective induction dose of remimazolam tosylate over 1 min (±5 s). When adequate sedation was achieved, colonoscopy was performed. Sedation was maintained at Modified Observer's Assessment of Alertness/Sedation (MOAA/S) ≤4 during the procedure. The additional administration of remimazolam tosylate (0.05 mg/kg per time) was permitted when necessary. Results: Forty-one patients, 39 patients and 40 patients were respectively analyzed in group A, group B and group C. The procedural success rate was 80.49%, 87.18% and 95.00% in group A, group B and group C, respectively. During the induction period, patients in group A required additional doses of remimazolam tosylate more frequently than in group B and group C, but less during the maintenance period (all P<0.05). There was no significant difference in the induction time or time to recovery among the three groups. Incidence of adverse events (such as hypotension, hyoxemia and bucking) was similar among the three groups. Conclusions: The initial loading doses of 0.1, 0.15, and 0.2 mg/kg remimazolam tosylate were all efficacy and safety for patients undergoing colonoscopy, and fewer times of the drug was re-administered. Trial Registration: Chinese Clinical Trial Registry ChiCTR2000041331.

12.
Langmuir ; 38(32): 9967-9973, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35916597

RESUMO

Integrated smart clothing with photothermal conversion and thermosensing functions is highly desired for next-generation smart wearable applications. Conducting polymer is a promising material that possesses efficient photothermal conversion performance, great sensitivity to temperature change, and excellent processing properties. In this study, we report a new wearable material using the conducting polymer polypyrrole (PPy) as a photothermal and thermosensing layer and nonwoven fabric as flexible textiles to fabricate integrated PPy-based smart clothing (IPSC). The surface temperature of the prepared IPSC can be as high as 68.4 °C with 808 nm near-infrared (NIR) irradiation at a power destiny of 1 kW/m2. Meanwhile, a temperature resolution of 1 °C can be achieved for IPSC. These superiorities are in favor of fabricating multifunctional smart wearables to satisfy the needs in future life.


Assuntos
Materiais Inteligentes , Dispositivos Eletrônicos Vestíveis , Polímeros , Pirróis , Sensação Térmica
13.
Int J Gen Med ; 15: 429-436, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35046704

RESUMO

BACKGROUND: Whether intraoperative temperature management can help patients recover quickly in the postanesthesia care unit (PACU) still remains to be investigated. This study aimed to investigate the effect of intraoperative temperature management on the quality of postoperative recovery of patients who underwent pulmonary lobectomy in the PACU. METHODS: Totally, 98 patients aged 45-60 years with a body mass index of 20-25 kg/m2 who underwent elective thoracoscopic lobectomy were enrolled. Patients were categorized into two groups using a random number table: the conventional group received routine intervention to maintain normothermia (Group C, n = 49) and the aggressive group received integrated interventions (Group A, n = 49). In Group C, normothermic fluid was infused intravenously, the heating blanket was turned on when the intraoperative temperature was <35.0 °C, and the warming was stopped when the temperature reached 36.5 °C. In Group A, the fluid heated to 37 °C was infused intravenously, and the heating blanket was used intraoperatively. When the body temperature was >37 °C, the heating blanket was turned off, and when the body temperature was <36.5 °C, the heating blanket was turned on to continue heating. RESULTS: Steward awakening scores at 1 min and 5 min after extubation and PaO2 levels at 15 min after extubation were higher in Group A than in Group C (P < 0.05); incidence of chills, nausea, and vomiting in the PACU was lower in Group A than in Group C (P < 0.05); and length of stay in the PACU was shorter in Group A than in Group C (P < 0.05). CONCLUSION: Aggressive intraoperative temperature management of patients undergoing thoracoscopic lobectomy can improve the quality of postoperative recovery in the PACU through a safe and smooth transition compared with routine insulation measures.

14.
ACS Appl Mater Interfaces ; 13(4): 5425-5434, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33496177

RESUMO

Pressure sensors for living organisms can monitor both the movement behavior of the organism and pressure changes of the organ, and they have vast perspectives for the health management information platform and disease diagnostics/treatment through the micropressure changes of organs. Although pressure sensors have been widely integrated with e-skin or other wearable systems for health monitoring, they have not been approved for comprehensive surveillance and monitoring of living organisms due to their unsatisfied sensing performance. To solve the problem, here, we introduce a novel structural design strategy to manufacture reduced graphene oxide-polypyrrole aerogel-based microfibers with a typical coaxial heterogeneous structure, which significantly enhances the sensitivity, resolution, and stability of the derived pressure microsensors. The as-fabricated pressure microsensors exhibit ultrahigh sensitivities of 12.84, 18.27, and 4.46 kPa-1 in the pressure ranges of 0-20, 20-40, and 40-65 Pa, respectively, high resolution (0.2 Pa), and good stability in 450 cycles. Furthermore, the microsensor is applied to detect the movement behavior and organic micropressure changes for mice and serves as a platform for monitoring micropressure for the integrative diagnosis both in vivo and in vitro of organisms.


Assuntos
Grafite/química , Polímeros/química , Pirróis/química , Dispositivos Eletrônicos Vestíveis , Animais , Técnicas Biossensoriais/instrumentação , Pressão Sanguínea , Condutividade Elétrica , Desenho de Equipamento , Feminino , Camundongos , Monitorização Fisiológica/instrumentação , Pressão , Têxteis/análise
15.
Colloids Surf B Biointerfaces ; 193: 111074, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416519

RESUMO

Bacteria easily adhere, colonize, and form biofilm on oral implants subsequently causing periimplantation periarthritis and mechanical loosening. Previous studies show that a high potential surface on polymeric implants can achieve surface bacteriostasis without side effects. In this study, a high surface potential is introduced to zirconia ceramics to mitigate bacterial infection. Carbon and nitrogen plasma immersion ion implantation (C-PIII and N-PIII) are conducted on zirconia ceramic samples sequentially to elevate the surface potential. The surface with a high potential but without ion leaching exhibits excellent antibacterial effects against oral bacteria and little bacterial resistance is triggered. The surface also has high strength and excellent biocompatibility. The nitrogen-containing inorganic structure with high potential can actualize bacteriostasis and biocompatibility on zirconia ceramics simultaneously and this new strategy can enhance the antibacterial ability of oral implants.


Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Cerâmica/farmacologia , Zircônio/farmacologia , Aggregatibacter actinomycetemcomitans/efeitos dos fármacos , Animais , Antibacterianos/química , Materiais Biocompatíveis/química , Células Cultivadas , Cerâmica/química , Teste de Materiais , Camundongos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Porphyromonas gingivalis/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Propriedades de Superfície , Zircônio/química
16.
ACS Appl Mater Interfaces ; 12(8): 9347-9354, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31994863

RESUMO

Aqueous zinc-ion batteries (AZIBs) are one of the promising choices for the future large-scale grid energy storage, in which Mn-based cathode materials have the advantages of low cost and environmental friendliness. However, their capacity delivery and cycling stability are limited by the large bulk-induced incomplete zincation and structure pulverization. Here, we develop a strategy of epitaxial polymerization in the liquid phase to fabricate two-dimensional (2D) MnOx/polypyrrole nanosheets to enhance the zinc-ion storage by realizing the efficient utilization of active materials and improving the structural stability via a polymerized framework. An ultrahigh capacity of 408 mAh g-1 is demonstrated at 1C rate, and an excellent capacity retention of 78% is realized after 2800 cycles at 5C rate for the AZIB. Electrochemical and morphological characterizations reveal that the unique 2D structure contributes to both the electron/ion conductivity and structural stability. The epitaxial polymerization of the conducting polymer in the liquid phase provides a new perspective to the synthesis of high-performance electrode materials and 2D conducting polymers.

17.
Adv Sci (Weinh) ; 8(1): 2001121, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33437568

RESUMO

Polymers shape human life but they also have been identified as pollutants in the oceans due to their long lifetime and low degradability. Recently, various researchers have studied the impact of (micro)plastics on marine life, biodiversity, and potential toxicity. Even if the consequences are still heavily discussed, prevention of unnecessary waste is desired. Especially, newly designed polymers that degrade in seawater are discussed as potential alternatives to commodity polymers in certain applications. Biodegradable polymers that degrade in vivo (used for biomedical applications) or during composting often exhibit too slow degradation rates in seawater. To date, no comprehensive summary for the degradation performance of polymers in seawater has been reported, nor are the studies for seawater-degradation following uniform standards. This review summarizes concepts, mechanisms, and other factors affecting the degradation process in seawater of several biodegradable polymers or polymer blends. As most of such materials cannot degrade or degrade too slowly, strategies and innovative routes for the preparation of seawater-degradable polymers with rapid degradation in natural environments are reviewed. It is believed that this selection will help to further understand and drive the development of seawater-degradable polymers.

18.
Nanoscale ; 11(24): 11730-11735, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31180401

RESUMO

Thermal dissipation and thermal insulation are important for maintaining the normal operation of devices, extending the service life of instruments, ensuring efficient energy utilization, and improving temperature-related human comfort. Yet it is difficult to achieve both the functions of thermal dissipation and thermal insulation in a single material with a specific thermal conductivity under specific conditions. In this work, based on the huge difference in thermal conductivity between air and reduced graphene oxide (rGO), a pressure-induced mechanism is used to regulate the amount of air inside an rGO foam, so that a periodic reversible change of thermal conductivity can be realized, achieving the dual functions of thermal dissipation and thermal insulation to meet the requirements of different application scenarios. Further fitting calculations suggest that the thermal conductivity of rGO foam is positively and negatively associated with the applied pressure and temperature, respectively, and it can be calculated for given pressure and temperature conditions. The pressure-induced reversible regulation of thermal conductivity in rGO foam provides a new design construct for smart thermal-management devices, and a new direction of application for 2D materials.

19.
Biomed Mater ; 14(4): 045008, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-30901762

RESUMO

Traditional broad-spectrum antibacterial agents are limited by high toxicity and the destruction to the bacterial flora balance in the wound site. Herein, we propose an opinion that one or several especial antibacterial peptides are adopted to kill the target bacteria in order to precisely manage the bacteria infected chronic wound under the premise of biobalance, and specially employ nisin to treat S. aureus infected chronic wound as model with positive effects. The results showed that without cytotoxicity to the normal cells, only 25 ppm nisin could contrapuntally kill S. aureus and have little inhibitory to other bacteria. Mechanism of antibacterial selectivity indicated the superior biomolecular interaction between nisin and S. aureus compared with E. coli and normal cells. Furthermore, nisin significantly accelerated the healing process of S. aureus-infected rabbit full thickness burn wound, but had no effect on the E. coli-infected wound as a comparison. Therefore, it has been demonstrated that special peptides with antibacterial selectivity can be adopted to precise management for bacteria infected chronic wound under good biobalance.


Assuntos
Antibacterianos/farmacologia , Queimaduras/terapia , Nisina/administração & dosagem , Nisina/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Arginina/química , Candida , Candida albicans , Sistemas de Liberação de Medicamentos , Escherichia coli , Concentração de Íons de Hidrogênio , Masculino , Testes de Sensibilidade Microbiana , Peptídeos/farmacologia , Pseudomonas aeruginosa , Coelhos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Streptococcus pneumoniae
20.
Des Monomers Polym ; 21(1): 33-42, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29706846

RESUMO

Poly (decamethylene terephthalamide) (PA10T) is a kind of engineering plastics with high strength and high modulus, but one of its disadvantages is its low elongation at break. In order to improve the flexibility of PA10T, one aliphatic comonomer with a long alkyl chain is introduced to the molecular chain of PA10T. Then long chain semiaromatic copolyamides 10T/1014 were synthesized with different contents of 1014 units by polycondensation reaction of 1,10-diaminodecane, terephthalic acid and 1,12-dodecanedicarboxylic acid in deionized water. The intrinsic viscosities of the resultant polyamides ranged from 0.90 to 1.03 dL/g were obtained. The chemical and crystal structures of the copolymers were characterized by FTIR, 1H-NMR and WAXD. These copolyamides exhibited outstanding thermal properties with melting points range of 306-295 °C and degradation temperatures range of 479-472 °C at maximum degradation rate, and also have a wider processing window than PA10T. The tensile strength of PA10T/1014 copolymers decreased gradually from 80.02 to 72.95 MPa as the content of 1014 units increasing from 5 to 20 mol %, while the elongation at break increased significantly from 57 to 150%. The moisture content of 10T/1014 copolyamides decreased with increasing the 1014 unit contents. It suggests that 10T/1014 copolyamides could be a kind of promising heat-resistant engineering thermoplastic in the future applications.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...