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Advanced Composite Biomaterials

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Nguyễn Gia Hào

Academic year: 2023

Chia sẻ "Advanced Composite Biomaterials"

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His work is primarily within polymeric membrane materials and processes in the Department of Analytical Chemistry and Environmental Engineering. Biomaterials is one of the most important fields of study in terms of development in the 21st century. In the field of optical properties, the capacity and coloring mechanism of horn claw (a biocompatible material obtained from biomass) is investigated.

In the field of precursors for implantable dental materials, a new composite based on poly(methyl methacrylate) and ZrO2 is reported, where the composite material shows remarkable mechanical properties compared to classical resin. Biomaterials" is one of the most important fields of study in terms of its development in the 21st century. In the field of the optical properties of biomaterials, the capacity and staining mechanism of horn claw (a biocompatible material obtained from biomass) were investigated [6].

Clogging of polymer membranes, especially by separations of viruses or bacteria, is a major problem in the separation of these species.

Figure 1. Evolution of the number of publications on Scopus and ISI Web of Knowledge containing
Figure 1. Evolution of the number of publications on Scopus and ISI Web of Knowledge containing

Tearable and Fillable Composite Sponges Capable of Heat Generation and Drug Release in Response to

  • Introduction
  • Experimental Section
  • Results and Discussion
  • Conclusions

MNPs with the highest saturation magnetization (MNP-8) were used to fabricate MNPs and DOX-loaded collagen sponge (MDC sponge). UV-vis spectra of the supernatant (400-800 nm wavelengths) were measured by UV-vis spectroscopy (V-670 spectrophotometer, JASCO, Tokyo, Japan). The temperature of the MDC sponge in the cell culture medium was measured every 30 s using an infrared thermal imaging camera.

Destructive ability of the MDC sponge on HeLa cells in the presence of an AMF. In the MDC sponges that were not cross-linked (Figure 3A), almost all of the DOX was released from the sponges within 10 min after immersion in PBS both at 37◦C (body temperature) and 45◦C (thermal treatment temperature). The viability of the tumor cells (HeLa cells) incubated with the MDC sponge for 3 and 5 days in the absence of AMF exposure was approximately 100% (Figure 7A,B), indicating that there was no DOX- release from the MDC sponge was not.

The degree of cross-linking of the MDC sponges was controlled by adjusting the cross-linking time.

Figure 1. Characteristics of the MNPs and DOX-loaded collagen (MDC) sponges. (A) Photograph of the MDC sponge and illustration showing its structure
Figure 1. Characteristics of the MNPs and DOX-loaded collagen (MDC) sponges. (A) Photograph of the MDC sponge and illustration showing its structure

Ligno-Cellulosic Fibre Sized with Nucleating Agents Promoting Transcrystallinity in Isotactic

Polypropylene Composites

  • Materials and Methods 1. Materials
  • Results
  • Discussion
  • Conclusions

It is used to reduce the cycle time and improve the tensile and flexural mechanical properties of iPP [42]. The addition of fibers to iPP had little effect on the overall crystallinity of the composites. The addition of NA also had little effect on the overall crystallinity of iPP, but the type of NA had a significant effect on the type of crystal structure present.

The addition of fiber to iPP without NA did not have a major impact on the melting temperature of the polymer, nor did the addition of theα-NA (Table 1). The addition of theβ-NA added a second melting peak at 152◦C (after removing the thermal history). Specimens were cut from the center of the cross-sectional area of ​​a tensile test specimen (dogbone).

The addition of fibers to iPP resulted in at least a doubling of the Young's modulus (Figure 4a). Furthermore, the addition of both NAs in the presence of fibers has no significant effect on the Young's modulus of the composites with the exception of α-NA with Tencel™ (+18%). Reinforcement of iPP with HT TMP fibers improved the impact strength of the composite (Figure 4c).

When added in conjunction with HT TMP fiber, the α-NA addition reduces the impact strength of the fiber composite compared to the addition of fiber alone. β-NA has no significant influence. Addition of α-NA resulted in no significant change, while addition of the β-NA resulted in moderate further improvement (+17%). In summary, the most important improvement for mechanical properties comes from the presence of the fibers themselves.

This study investigated the effect of coating lignocellulosic fibers with NA on the mechanical properties of the resulting iPP-fiber composite. The tensile strength and impact strength of fiber-iPP composite are not significantly improved by NA. Investigation of the dynamic crystallization and melting behavior of isotactic β-nucleated polypropylene with different stereodefect distributions - The role of a doubly selective β-nucleating agent.

A comparison of the mechanical properties of poly (lactic acid) (pla) and poly (3-hydroxybutyrate) (phb) composites reinforced with kenaf and lyocell fibers.

Figure 1. Optical micrographs of iPP trans-crystallisation around High Temperature Thermo-Mechanical Pulp fibres (HT TMP) and Tencel™ fibres with different sizing
Figure 1. Optical micrographs of iPP trans-crystallisation around High Temperature Thermo-Mechanical Pulp fibres (HT TMP) and Tencel™ fibres with different sizing

Ultralight Industrial Bamboo Residue-Derived Holocellulose Thermal Insulation Aerogels with

Figure 3 shows the FT-IR spectra of HCNF, HCNF/APP and HCNF/APP/MTMS aerogels. 770 cm−1, appears in the HCNF/APP/MTMS aerogels, and the C–H deformation vibrations of –CH3at ca. The XRD patterns of HCNF, HCNF/APP and HCNF/APP/MTMS aerogels are shown in Figure 4 .

To further study the properties of the modified aerogels, Figure 6 shows the morphology of HCNF and HCNF/APP/MTMS aerogels. The compressive properties of HCNF, HCNF/APP, and HCNF/APP/MTMS aerogels are shown in Figure 8. However, the HCNF/APP/MTMS aerogels did not burn when contacted with a butane blowtorch flame.

As shown in Figure 10a, the HRR of HCNF/APP/MTMS aerogels was noticeably reduced compared to HCNF aerogels. However, more continuous carbon layers and the stable porous structure were preserved in the HCNF/APP/MTMS aerogels after testing the cone calorimeter. This behavior showed that the APP and MTMS played a key role in improving the fire resistance of HCNF/APP/MTMS aerogels.

And the stable porous structure of HCNF/APP/MTMS aerogels can effectively absorb some of the smoke [39]. Moreover, with the addition of APP and MTMS, the thermal conductivity of HCNF/APP/MTMS aerogels increased to 0.039 W/m·K. In addition, APP and MTMS changed the structure of HCNF/APP/MTMS aerogels, causing it to form a 3D network opening structure.

In general, the thermal conductivity of the HCNF and HCNF/APP/MTMS aerogels ranged from 0.0285 to 0.039 W/m K. The HCNF/APP/MTMS aerogels showed reduced compressive strength due to the structural changes after APP and MTMS.

Figure 1. The mechanism scheme for HCNF/APP/MTMS aerogels.
Figure 1. The mechanism scheme for HCNF/APP/MTMS aerogels.

Synthesis and Characterization of PLA-Micro-structured Hydroxyapatite

Materials and Methods

Figure 1 shows the FT-IR spectra of the HA, PLA and PLA/HA composite films. The spectra of the composite membranes are similar to the PLA spectrum and exhibit only the vibrational bands corresponding to the polymer structure. This band comes from the HA structure and represents a piece of quite solid evidence for the presence of the inorganic compound in the polymer matrix.

The absence of this band in the case of the composite membrane's spectrum with 1 wt.% HA. Thermogravimetric analysis was used to study the effect of HA nanoparticles on the thermostability of the polymer. An increase in the thermostability of the composite films with 1 and 2 wt% HA loaded was observed at about 53◦C compared to pure PLA.

In addition, the presence of an exothermic peak around 106 °C can be observed on the DSC curves, which corresponds to the crystallinity of the polymer (cold crystallization - crystallization temperature - Tc). It can be observed that at a low concentration of HA (1 wt. %), the crystallinity of the composite films significantly decreased compared to the pure polymer. However, this value was below the crystallinity obtained in the case of pure polymer.

This could be explained by the fact that the presence of a small amount of HA (less than 4% by weight) leads to a decrease in the crystallinity of HA. As the amount of HA particles in the structure of the film increases, large crystals have a larger volume [29,37,38]. The presence of HA on the porous surface can be explained by the weight of the particles, which are gravity deposited on the base of the film of the polymer solution.

According to the figure and Table 2, a slight decrease in Young's modulus can be observed in the case of the composite films with 2 and 4 wt.% HA loaded within the polymer matrices. There was a significant decrease in the crystallinity of the composite films compared to the pure polymer, which is explained by the decrease in the arrangement of the polymer chains and a simultaneous increase in their degree of disorder.

Figure 1. FT-IR spectra of hydroxyapatite (HA) and polylactic acid (PLA)/HA composite films.
Figure 1. FT-IR spectra of hydroxyapatite (HA) and polylactic acid (PLA)/HA composite films.

Preparation and Performance of Radiata-Pine-Derived Polyvinyl Alcohol/Carbon Quantum Dots

Fluorescent Films

Figure 5 shows the images of the prepared PVA, PVA/CQD, PVA/CNF and PVA/CNF/CQD films under ultraviolet rays (UV rays) with a wavelength of 365 nm. When the loading of CQDs in the PVA/CQD composites increases from 0.2 to 2 mL (from No. 2 to No. 4), the fluorescence intensity of the films increases sequentially; this is due to the increased dosage of CQD in the composites. The fluorescence intensity of the prepared PVA/CNF/CQD films gradually increases as the dose of CQDs increases from 0.2 to 2 mL (from No. 7 to No. 9).

When this dose exceeds 2 ml (No. 10), the fluorescence intensity of the PVA/CNF/CQDs films no longer increases, or even starts to decrease. Figure 7 displays the optical performance of the prepared films with different contents of CQDs (No. 1 to No. 10), at the excitation wavelength of 365 nm. For PVA/CQDs films and PVA/CNF/CQDs films, the transmittance of the films decreased with the increase in the dose of CQDs.

This indicates that barrier property to light of the films improves after the addition of CQDs. Figure 10 gives SEM plots of the fracture section of PVA, PVA/CQDs, PVA/CNF and PVA/CNF/CQDs films. Meanwhile, the water absorption of PVA/CNF/CQDs films (0.2 mL) is higher than that of PVA/CNF films, which is consistent with the previous one; that is, the increase in water absorption of the films is due to the introduction of CQDs.

This suggests that changing the CQDs content can affect the water absorption of the films. Compared to the water absorption of PVA/CQDs (No. 1–No. 5), the water absorption of the PVA/CNF/CQDs (No. 6 to No. 10) films decreases significantly. Therefore, the surface polar groups of the PVA-based films have less contact with water molecules [80].

The contact angles of the films (No. 1 to No. 10) fall within a narrow range due to the fact that the composites have a large amount of the hydrophilic groups. This suggests that the wettability of the PVA/CQDs film (No. 2) and PVA/CNF/CQDs film (No. 7) is worse than that of the pure PVA film and the PVA/CNF films, respectively. This indicates that the hydrophilicity of the films does not change with the introduction of CQDs.

With the increase of the CQD content, the water contact angle decreases, which leads to an improvement in the wettability of the prepared films.

Figure 1. (a) Filtered CQDs solution; (b) dialysis CQDs solution.
Figure 1. (a) Filtered CQDs solution; (b) dialysis CQDs solution.

Hình ảnh

Figure 1. Evolution of the number of publications on Scopus and ISI Web of Knowledge containing
Figure 3. DOX release from the MDC sponge without crosslinking treatment (A) and with 1.5 h (B), 6 h (C), and 24 h (D) crosslinking treatment in phosphate-buffered saline (PBS) and the absence of alternating magnetic field (AMF) at 37 ◦ C and 45 ◦ C.
Figure 4. Magnetization curve of the MDC sponge at room temperature.
Figure 7. Viability of untreated HeLa cells incubated without sponges and AMF application, with the MDC sponge and no AMF application, with MC sponge (without DOX) and 15-min AMF application, and with MDC sponge and 15-min AMF application at 3 (A) and 5 (B
+7

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