Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Hazard Mater ; 423(Pt A): 127054, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34481389

RESUMO

Currently, many catalysts are inconvenient to separate from water, and the solvents used in the preparation process are not environmentally friendly, resulting in low recovery efficiency and secondary pollution. In this study, the magnetic and porous regenerated cellulose/carbon nanotubes/Fe3O4 nanoparticles (RC/CNTs/Fe3O4 NPs) composites were synthesized for activation of peroxydisulfate (PDS) in a green alkaline-urea system. The RC/CNTs/Fe3O4 NPs-PDS system achieved 100% removal of bisphenol A compared with CNTs (~64.6%), RC (~0%) or Fe3O4 NPs (~0%), which was closely related to the introduction of defects and functional groups, nitrogen doping and conductive networks. Interestingly, the strong interaction between CNTs and the sheath-like protective layer formed by urea on the cellulose surface promotes the introduction of nitrogen into the composites at the preparation temperature of 70 °C. Moreover, the mechanism of the system was found to be a typical non-radical pathway. Fortunately, there is no leaching of iron ions in the system, and the effects of the actual waterbody, initial pH, and different anions are negligible. The recycling and separation experiments revealed the practicality and superiority of the composite. This work provides a feasible and sustainable strategy for the application of natural cellulose-supported catalysts.


Assuntos
Nanotubos de Carbono , Compostos Benzidrílicos , Celulose , Fenóis
2.
Nat Commun ; 12(1): 675, 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514696

RESUMO

Piezoelectric polymers hold great potential for various electromechanical applications, but only show low performance, with |d33 | < 30 pC/N. We prepare a highly piezoelectric polymer (d33 = -62 pC/N) based on a biaxially oriented poly(vinylidene fluoride) (BOPVDF, crystallinity = 0.52). After unidirectional poling, macroscopically aligned samples with pure ß crystals are achieved, which show a high spontaneous polarization (Ps) of 140 mC/m2. Given the theoretical limit of Ps,ß = 188 mC/m2 for the neat ß crystal, the high Ps cannot be explained by the crystalline-amorphous two-phase model (i.e., Ps,ß = 270 mC/m2). Instead, we deduce that a significant amount (at least 0.25) of an oriented amorphous fraction (OAF) must be present between these two phases. Experimental data suggest that the mobile OAF resulted in the negative and high d33 for the poled BOPVDF. The plausibility of this conclusion is supported by molecular dynamics simulations.

3.
ACS Omega ; 4(1): 509-517, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-31459345

RESUMO

Regenerated cellulose (RC) films exhibit poor water barrier performance, which seriously restricts its applications. To address this issue, an impermeable and hydrophobic graphene oxide modified by chemically grafting octadecylamine (GO-ODA) was utilized to enhance the water vapor barrier performance of RC nanocomposite films. Compared to the neat RC film, more than 20% decrease in the coefficient of water vapor permeability (P H2O) was achieved by loading only 2.0 wt % GO-ODA. The promising hydrophobicity of GO-ODA effectively retarded the formation of hydrogen bonding at the relatively weakened interface between GO and RC, compensating for the diffusion of water vapor molecules at the interface; on the other hand, the fully exfoliated GO-ODA nanosheets were inclined to align with the surface of the as-prepared RC nanocomposite films during hot-pressure drying, creating a much more tortuous pathway for diffusion of water molecules. The new insights could be valuable for widening application of cellulose such as packaging.

4.
Biomacromolecules ; 20(7): 2754-2762, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31125205

RESUMO

Substantial adsorption of water vapor triggered by hydrogen-bonding interactions between water molecules and cellulose chains (or nanoplates) is hard to avoid in nanocomposite films, although the addition of nanoplates can improve the oxygen (or carbon dioxide) barrier property. In the present work, an effective strategy is raised to decline adsorption by weakening hydrogen-bonding interactions via chemical cross-linking by epichlorohydrin (ECH) without sacrificing the homogeneous dispersion of nanoplates. The generated microdomain structure of the chemical cross-linking reaction via ECH is explicitly revealed by micro-Raman imaging. Unambiguously, Raman maps of scanning elucidate the distribution and morphology of physical and chemical cross-linking domains quantitatively. The chemical cross-linking domains are nearly uniformly located in the matrix at a low degree of cross-linking, while the interconnected and assembled networks are formed at a high degree of cross-linking. ECH boosts the formation of chemical cross-linking microdomains, bringing out the terrific water vapor barrier property and alleviating the interfacial interactions in penetration, consequently magnifying the water contact angle and holding back the water vapor permeability. Our methodology confers an effective and convenient strategy to obtain remarkable water vapor-resistant cellulose-based films that meet the practical application in the packaging fields.


Assuntos
Celulose/química , Epicloroidrina/química , Nanocompostos/química , Água/química , Celulose/farmacologia , Reagentes para Ligações Cruzadas/química , Reagentes para Ligações Cruzadas/farmacologia , Epicloroidrina/farmacologia , Ligação de Hidrogênio/efeitos dos fármacos , Permeabilidade/efeitos dos fármacos , Análise Espectral Raman , Vapor
5.
Carbohydr Polym ; 211: 237-248, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30824085

RESUMO

Cellulose films are of poor water-vapor barrier performance. Herein, we put forward an effective way to suppress adsorption by crosslinking of hydroxyl groups via epichlorohydrin (ECH), meanwhile graphene oxide (GO) nanosheets are utilized to prolong the pathway of vapor penetration. The strategy confers a significant enhancement of vapor barrier performance as well as mechanical properties to cellulose-based films. Specifically, an outstanding reduction of 67.4% in water-vapor permeability coefficient is achieved in nanocomposite films compared to the uncrosslinked cellulose films. Furthermore, for the first time, two-dimensional correlation analysis reveals that crosslinking of ECH do not alter penetration direction, while GO can eminently act as shielding for the formation of bound water which change the sequential order of firstly-interacted vapor area from crystalline to amorphous area. Free volume is the penetration destination. The retarding effect introduced by the GO in amorphous area gives rise to the improvement of the vapor-barrier.

7.
ACS Appl Mater Interfaces ; 11(1): 1680-1688, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30520621

RESUMO

Superhydrophobic electromagnetic interference (EMI) shielding textile (EMIST) is of great significance to the safety and long-term service of all-weather outdoor equipment. However, it is still challenging to achieve long-term durability and stability under external mechanical deformations or other harsh service conditions. Herein, by designing and implementing silver nanowire (AgNW) networks and a superhydrophobic coating onto a commercial textile, we demonstrate a highly robust superhydrophobic EMIST. The resultant EMIST shows a synergy of high water contact angle (160.8°), low sliding angle (2.9°), and superior EMI shielding effectiveness (51.5 dB). Remarkably, the EMIST still maintains its superhydrophobic feature and high EMI shielding level (42.6 dB) even after 5000 stretching-releasing cycles. Moreover, the EMIST exhibits strong resistance to ultrasonic treatment up to 60 min, peeling test up to 100 cycles, strong acidic/alkaline solutions, and different organic solvents, indicating its outstanding mechanical robustness and chemical durability. These attractive features of the EMIST are mainly a result of the joint action of AgNWs, carbon nanotubes, polytetrafluoroethylene nanoparticles, and fluoroacrylic polymer. This work offers a promising approach for the design of future durable, superhydrophobic EMISTs, which are capable of remaining fully functional against long-time exposure to extreme conditions, for example, wet and corrosive environments.

8.
ACS Appl Bio Mater ; 2(3): 1357-1367, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-35021382

RESUMO

Heat-resistant poly(l-lactide) (PLLA) barrier biocomposites with full biodegradability were realized through the construction of locally oriented and compact transcrystallinity supernetworks in the network of high-melting-point poly(l-lactide) (hPLLA) nonwoven fabrics composed of high-efficiency nucleating hPLLA fiber through design of two types of sandwich architectures for PLLA/hPLLA nonwoven fabrics, where single or double hPLLA nonwoven fabrics were introduced at the core or two sides of PLLA matrix film, respectively. The hPLLA fiber induced dense and oriented PLLA transcrystallinity in networks of hPLLA nonwoven fabrics and impermeable crystalline layers were formed with well-interlinked lamellae, which served as impermeable barriers to oxygen and water vapor molecules. Moreover, hPLLA nonwoven fabrics involving the compact transcrystallinity behaved as framework to support the PLLA matrix and resist the thermal deformation. The sandwich-architectured PLLA with double hPLLA nonwoven fabrics exhibited better barrier properties and heat resistance than that with single hPLLA nonwoven fabrics. Compared with neat PLLA, the oxygen permeability coefficient and water permeability coefficient of PLLA/double hPLLA nonwoven fabric biocomposites significantly decreased by 61.7% and 58.7%, and the storage modulus increased by a factor of 160 at 80 °C. This work provides a novel method to fabricate heat-resistant PLLA barrier film with full biodegradability for packaging application.

9.
ACS Appl Mater Interfaces ; 10(48): 41637-41644, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30395431

RESUMO

Personal cooling technologies (PCTs) locally control the temperature of an individual instead of a whole building and are thus energy saving. However, most PCTs still consume energy and are heavy in weight, restricting their application among human beings. To achieve personal thermal comfort and no energy consumption on hot summer days, we designed a bilayer structure fabric with high thermal comfort by increasing the dissipation of human thermal radiation and reducing solar energy absorption simultaneously. The fabric consisted of two layers, including a polyethylene film with nanopores (100-1000 nm in pore size) and a film made of nylon 6 nanofibers (ca. 100 nm in diameter) with beads (ca. 230 nm in diameter), which could increase the visible light reflectance but not affect the infrared wave radiation. Therefore, the designed fabric showed a high heat dissipation power, which was 14.13, 17.93, and 17.93 W/m2 higher than that of the selected traditional textiles of cotton, linen, and odile, respectively, suggesting good cooling capability. Its cooling performance was better than those reported by the previous research works even at a higher ambient temperature. Meanwhile, the moisture penetrability and hygroscopic property results indicated that the wearing comfort of the designed fabric reached the levels of the selected traditional textiles.


Assuntos
Temperatura Corporal , Raios Infravermelhos , Nylons , Polietileno , Têxteis , Humanos
10.
ACS Appl Mater Interfaces ; 10(46): 40156-40167, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30383958

RESUMO

Lightweight conductive polymer composites based on biomass could be a promising candidate for electromagnetic interference (EMI) shielding application. Herein, tailoring porous microstructure and regulating the distribution of carbon nanotubes (CNTs) in cellulose composites are attempts to achieve highly efficient EMI shielding properties accompanying desired mechanical property and low density. Specifically, aligned porous structure is fabricated by ice-template freeze-drying method; meanwhile, CNT is regulated to decorate inside the cellulose matrix (CNT-matrix/cellulose porous composites) or to directly bind over the cellulose cell walls (CNT-interface/cellulose porous composites). It is found that, owing to the preferential distribution of CNT on the cell walls, the CNT-interface/cellulose porous composites possess a very high electrical conductivity of 38.9 S m-1 with an extremely low percolation threshold of 0.0083 vol % with regard to CNT-matrix/cellulose porous composites. Therefore, a shielding effectiveness of 40 dB with merely 0.51 vol % CNT under a thickness of 2.5 mm is achieved in CNT-interface/cellulose porous composites, which is attributed to efficient multiple reflections and the accompanying absorption with promoted conductivity and better-defined porous structure. More laudably, the CNT-interface/cellulose porous composites reveal a superior mechanical property with a specific modulus of 279 MPa g-1 cm3. The value behind the current work is to pave an effective way to fabricate environmentally benign, high-performance EMI shielding materials to practically boost numerous advanced applications of cellulose.

12.
Carbohydr Polym ; 179: 244-251, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29111048

RESUMO

The ultra-high mechanical, biocompatible and biodegradable porous regenerated cellulose/poly(ethylene glycol) (RC/PEG) composites with double network structure were fabricated via an simple method to dissolve cellulose followed by UV irradiation. The porous structure of RC/PEG was sensitively altered by PEG contents, which led to the porous structure morphology transition from 3D fibrillar network to close-grained sheet-like-network with the loading of cross-linked PEG. The porous RC/PEG showed excellent mechanical properties, i.e., the compressive strength can reach 33 times higher than that of neat RC (0.07MPa) at the compressive strain of 30%. Porous RC/PEG also displayed outstanding properties with openly porous structure and structural stabilization. Besides, porous RC/PEG exhibited good water absorbency, which the water absorbency ratio at equilibrium state was 83% higher than that of porous RC. This work provides an environmentally friendly and simple pathway to prepare non-toxic and biocompatible porous regenerated cellulose-based composites with high strength, structural stabilization and good water absorbency, which could be useful for packaging, biomedical applications, sewage purification, etc.

13.
ACS Appl Mater Interfaces ; 9(11): 10148-10159, 2017 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-28252280

RESUMO

The challenge of hitherto elaborating a feasible pathway to overcome the conflicts between strength and toughness of polylactide (PLA) still remains among academia and industry. In the current work, a unique hierarchal structure of flexible poly(butylene adipate-co-terephthalate) (PBAT) in situ nanofibrils integrating with abundant PLA shish-kebabs as a strong building block was disclosed and expresses its capability to conquer this dilemma. Substantially simultaneous enhancement on tensile strength, impact strength, and elongation at break could be achieved up to 91.2 MPa, 14.9 KJ/m2, and 15.7%, respectively, compared with pure PLA (61.5 MPa, 4.3 KJ/m2, and 6.2%). Through investigating the phase (and crystalline) morphology and molecular chain behavior in the PLA/PBAT system, the formation mechanism of this structure facilitated by a coupling effect of PBAT flexible phase and shear flow was definitely elucidated. The dispersed phase of PBAT would be more inclined to existing as a fibrillar form within the PLA matrix benefiting from low interfacial tension. Interestingly, this phase morphology with large specific surface area changes the crystallization behavior of PLA significantly, once introducing an intense shear flow (∼103 s-1), in situ shear-formed nanofibrils of PBAT would show strong coupling effect with shear flow on PLA crystallization: they can not only induce abundant shish-kebabs of PLA at its interfaces, which possesses lengthened shish and more densely arranged kebabs, but also further retard the relaxation of PLA chains through hysteretic relaxation of its PBAT phase, which can effectively prevent the collapse of established shish. Of immense significance is this particular hierarchical-architecture composed by flexible nanofibers (PBAT) and rigid shish-kebabs (PLA), which provides significant guidance for the simultaneous reinforcement and toughness of polymer materials.

14.
Polymers (Basel) ; 9(9)2017 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-30965749

RESUMO

In the past few decades, Poly(vinylidene fluoride)/Polymethylmethacrylate (PVDF/PMMA) binary blend has attracted substantial attention in the scientific community due to possible intriguing mechanical, optical and ferroelectric properties that are closely related to its multiple crystal structures/phases. However, the effect of PMMA phase on the polymorphism of PVDF, especially the relationship between miscibility and polymorphism, remains an open question and is not yet fully understood. In this work, three series of particle blends with varied levels of miscibility between PVDF and PMMA were prepared via seeded emulsion polymerization: PVDF⁻PMMA core⁻shell particle (PVDF@PMMA) with high miscibility; PVDF/PMMA latex blend with modest miscibility; and PVDF@c⁻PMMA (crosslinked PMMA) core⁻shell particle with negligible miscibility. The difference in miscibility, and the corresponding morphology and polymorphism were systematically studied to correlate the PMMA/PVDF miscibility with PVDF polymorphism. It is of interest to observe that the formation of polar ß/γ phase during melt crystallization could be governed in two ways: dipole⁻dipole interaction and fast crystallization. For PVDF@PMMA and PVDF/PMMA systems, in which fast crystallization was unlikely triggered, higher content of ß/γ phase, and intense suppression of crystallization temperature and capacity were observed in PVDF@PMMA, because high miscibility favored a higher intensity of overall dipole⁻dipole interaction and a longer interaction time. For PVDF@c⁻PMMA system, after a complete coverage of PVDF seeds by PMMA shells, nearly pure ß/γ phase was obtained owing to the fast homogeneous nucleation. This is the first report that high miscibility between PVDF and PMMA could favor the formation of ß/γ phase.

15.
Sci Rep ; 6: 34572, 2016 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-27694989

RESUMO

Despite the enormous potential in bioinspired fabrication of high-strength structure by mimicking the spinning process of spider silk, currently accessible routes (e.g., microfluidic and electrospinning approaches) still have substantial function gaps in providing precision control over the nanofibrillar superstructure, crystalline morphology or molecular orientation. Here the concept of biomimetic nanofibrillation, by copying the spiders' spinning principles, was conceived to build silk-mimicking hierarchies in two-phase biodegradable blends, strategically involving the stepwise integration of elongational shear and high-pressure shear. Phase separation confined on nanoscale, together with deformation of discrete phases and pre-alignment of polymer chains, was triggered in the elongational shear, conferring the readiness for direct nanofibrillation in the latter shearing stage. The orderly aligned nanofibrils, featuring an ultralow diameter of around 100 nm and the "rigid-soft" system crosslinked by nanocrystal domains like silk protein dopes, were secreted by fine nanochannels. The incorporation of multiscale silk-mimicking structures afforded exceptional combination of strength, ductility and toughness for the nanofibrillar polymer composites. The proposed spider spinning-mimicking strategy, offering the biomimetic function integration unattainable with current approaches, may prompt materials scientists to pursue biopolymer mimics of silk with high performance yet light weight.


Assuntos
Materiais Biomiméticos/química , Nanofibras/química , Seda/química , Aranhas , Animais
16.
ACS Appl Mater Interfaces ; 8(12): 8096-109, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26959220

RESUMO

Remarkable combination of excellent gas barrier performance, high strength, and toughness was realized in polylactide (PLA) composite films by constructing the supernetworks of oriented and pyknotic crystals with the assistance of ductile in situ nanofibrils of poly(butylene adipate-co-terephthalate) (PBAT). On the basis that the permeation of gas molecules through polymer materials with anisotropic structure would be more frustrated, we believe that oriented crystalline textures cooperating with inerratic amorphism can be favorable for the enhancement of gas barrier property. By taking full advantage of intensively elongational flow field, the dispersed phase of PBAT in situ forms into nanofibrils, and simultaneously sufficient row-nuclei for PLA are induced. After appropriate thermal treatment with the acceleration effect of PBAT on PLA crystallization, oriented lamellae of PLA tend to be more perfect in a preferential direction and constitute into a kind of network interconnecting with each other. At the same time, the molecular chains between lamellae tend to be more extended. This unique structure manifests superior ability in ameliorating the performance of PLA film. The oxygen permeability coefficient can be achieved as low as 2 × 10(-15) cm(3) cm cm(-2) s(-1) Pa(-1), combining with the high strength, modulus, and ductility (104.5 MPa, 3484 MPa, and 110.6%, respectively). The methodology proposed in this work presents an industrially scalable processing method to fabricate super-robust PLA barrier films. It would indeed push the usability of biopolymers forward, and certainly prompt wider application of biodegradable polymers in the fields of environmental protection such as food packaging, medical packaging, and biodegradable mulch.


Assuntos
Membranas Artificiais , Nanofibras/química , Oxigênio/química , Poliésteres/química , Permeabilidade
18.
ACS Appl Mater Interfaces ; 8(1): 455-65, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26698912

RESUMO

Understanding nonlinear dielectric behavior in polar polymers is crucial to their potential application as next generation high energy density and low loss dielectrics. In this work, we studied nonlinear dielectric properties of a biaxially oriented poly(vinylidene fluoride) (BOPVDF) film under both low and high electric fields. For fundamental nonlinear dielectric constants at low fields (<30 MV/m), Novocontrol high-voltage broadband dielectric spectroscopy (HVBDS) was accurate enough to measure up to the third harmonics. It was observed that the low-field dielectric nonlinearity for the BOPVDF disappeared above 10 Hz at room temperature, suggesting that the low-field dielectric nonlinearity originated from ionic migration of impurity ions rather than dipolar relaxation of the amorphous segments. Above the coercive field (EC ≈ 70 MV/m), bipolar electric displacement-electric field (D-E) loop tests were used to extract the nonlinear behavior for pure PVDF crystals, which had a clear origin of ferroelectric switching of polar crystalline dipoles and domains and nonpolar-to-polar (α → δ → ß) phase transformations. By using HVBDS, it was observed that the ferroelectric switching of polar crystalline dipoles and domains in BOPVDF above the EC always took place between 20 and 500 Hz regardless of a broad range of temperature from -30 to 100 °C. This behavior was drastically different from that of the amorphous PVDF dipoles, which had a strong dependence on frequency over orders of magnitude.

19.
ACS Appl Mater Interfaces ; 7(15): 8023-32, 2015 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-25826123

RESUMO

The traditional approach toward barrier property enhancement of poly(lactic acid) (PLA) is the incorporation of sheet-like fillers such as nanoclay and graphene, unfortunately leading to the sacrificed biocompatibility and degradability. Here we unveil the first application of a confined flaking technique to establish the degradable nanolaminar poly(butylene succinate) (PBS) in PLA films based on PLA/PBS in situ nanofibrillar composites. The combination of high pressure (10 MPa) and appropriate temperature (160 °C) during the flaking process desirably enabled sufficient deformation of PBS nanofibrils and retention of ordered PLA channels. Particularly, interlinked and individual nanosheets were created in composite films containing 10 and 20 wt % PBS, respectively, both of which presented desirable alignment and large width/thickness ratio (nanoscale thickness with a width of 428±13.1 and 76.9±8.2 µm, respectively). With the creation of compact polymer "nano-barrier walls", a dramatic decrease of 86% and 67% in the oxygen permeability coefficient was observed for the film incorporated with well-organized 20 wt % PBS nanosheets compared to pure PLA and pure PBS (1.4 and 0.6×10(-14) cm3·cm·cm(-2)·s(-1)·Pa(-1)), respectively. Unexpectedly, prominent increases of 21% and 28% were achieved in the tensile strength and modulus of composite films loaded 20 wt % PBS nanosheets compared to pure PLA films, although PBS intrinsically presents poor strength and stiffness. The unusual combination of barrier and mechanical performances established in the fully degradable system represent specific properties required in packaging beverages, food and medicine.


Assuntos
Plásticos Biodegradáveis/síntese química , Butileno Glicóis/química , Química Verde/métodos , Ácido Láctico/química , Membranas Artificiais , Nanofibras/química , Polímeros/química , Elasticidade , Teste de Materiais , Nanofibras/ultraestrutura , Poliésteres , Resistência à Tração
20.
J Phys Chem B ; 119(13): 4777-87, 2015 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-25761561

RESUMO

Following our previous work on graphene oxide-induced polylactide (PLA) crystallization [Macromolecules 2010, 43, 5000-5008], in the current work, we further revealed the role of size and structural integrity of thermally reduced graphene oxide (RGO) in PLA crystallization. RGO nanoplatelets with different architectures were obtained via bath and probe ultrasound (RGOw and RGOp). The average size of RGO decreased substantially with ultrasound intensity and time, where the generation of RGO edges constituted the translocation of functional group sites from in-plane to edges. The formation of sp(3)-configuration dominated in RGOw, whereas the partial recovery of sp(2)-configuration occurred in RGOp, giving rise to either the escalation of sp(3)/sp(2) ratio for RGOw or retrogradation of that for RGOp. Isothermal crystallization kinetics of PLA nanocomposites containing RGOw and RGOp was determined by in situ synchrotron wide-angle X-ray diffraction. The induction period and overall crystallization rate of PLA/RGOw nanocomposites were strengthened with diminishing platelet size because of more nucleation sites encouraged by redistribution of functional groups. However, the adverse situation was found in PLA/RGOp nanocomposites. The observed phenomenon was ascribed to the disruption of the internal structure, i.e., the C═C sp(2) π-bond network, which deteriorated the CH-π interaction between PLA and RGO. These results conclusively suggested that the size and structural integrity of RGO had a concerted effort to determine the final nucleation ability of RGO dispersed by ultrasound.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...