Methods of determining the degree of crystallinity of polymers with X-ray diffraction: a review

Uzun, İlhan

doi:10.1007/s10965-023-03744-0

Cited by 11 publications

(5 citation statements)

References 280 publications

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“…The molecular dynamics simulation is shown in Figure S4. Therefore, the CI-PI chains were better ordered and exhibited higher alignment, as demonstrated in subsequent density measurements. As presented in Figure d, by heating the same CI-PAA sample from 80 to 200 °C, CI-PAA imidization at low temperatures could be studied in detail.…”

Section: Resultsmentioning

confidence: 99%

Cross-Linking Synergistic Effects to Enhance the Comprehensive Properties of Electrospun Polyimide Nanofiber Membranes for Advanced Lithium-Ion Batteries

Chen,

Song,

Liu

et al. 2024

ACS Sustainable Chem. Eng.

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Electrospun polyimide (PI) nanofiber membranes have served as promising separators for safe lithium-ion batteries (LIBs) due to their excellent thermal stability. However, electrospun PI nanofiber membranes have excessively large pores and low mechanical strength, which have been shown to be unsuitable for direct utilization as LIB separators. To solve these issues, we proposed a novel electrospun PI nanofiber membrane obtained using a triple cross-linking strategy, including precalendering, microsolvent dissolution, and chemical imidization. The precalendering process, as a prerequisite, densified the poly(amic acid) (PAA) nanofiber membrane and followed by microsolvent dissolution and chemical imidization, which provided synergistic cross-linking effects. This resulted in a mutual anchoring effect of the ultralong molecular chains at the cross-linking interface, forming a robust cross-linking structure and efficient imidization transition. As a result, the mechanical properties of the samples significantly improved, while the tensile strength increased from 9.9 to 95.5 MPa. Furthermore, as the pressing degree of the membranes increased, the electrolyte uptake, ionic conductivity, and capacity decreased; however, the ability to inhibit lithium dendrite growth and uniformly produce solid electrolyte interfaces (SEIs) increased. Compared to the noncross-linked PI membrane, the PI membrane obtained using the triple cross-linking strategy had a stable interface with the lithium metal electrodes and a high-capacity retention rate. This robust PI nanofiber membrane could serve as a promising replacement for traditional polyolefin separators in high-performance LIBs.

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Section: Resultsmentioning

confidence: 99%

Cross-Linking Synergistic Effects to Enhance the Comprehensive Properties of Electrospun Polyimide Nanofiber Membranes for Advanced Lithium-Ion Batteries

Chen,

Song,

Liu

et al. 2024

ACS Sustainable Chem. Eng.

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“…X-ray diffraction (XRD) measurement was employed to characterize the crystalline structures of chitin powders using a DX-1000 diffractometer. By selecting the XRD crystallization peaks of PVA components, the crystallinity of PVA in PVA/chitin composite materials was measured and calculated using the following equation c r y s t a l l i n i t y .25em ( % ) = F normalc F c + F a × 100 …”

Section: Methodsmentioning

confidence: 99%

Solid-State Utilization of Chitin to Construct Flexible Films with Enhanced Biocompatibility and Mechanical Performance

Ye,

Wang,

Wang

et al. 2024

ACS Sustainable Chem. Eng.

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The resource utilization of biomass materials has ignited increasing interest owing to their renewability, biodegradability, and abundance. However, the most representative biomass materials, such as cellulose and chitin, are faced with challenges in terms of the difficulty of thermal processing and the inability of scalable production due to the strong hydrogen bonding between molecular chains. Herein, the large-sized chitin scraps were efficiently pulverized and exfoliated through solid-state shear milling (S 3 M) technology at room temperature. The strong shearing and squeezing force generated from the two pans could further induce the in situ compatibilization of chitin and another environmentally friendly polymer, poly(vinyl alcohol) (PVA). In this way, the flexible PVA/chitin composite film was successfully prepared via thermal processing, attributed to the plasticizing method and perfect film-forming performance of PVA. The ultrafine-pulverized and well-dispersed chitin could effectively promote cell adhesion and proliferation and further enhance the mechanical properties of the composite film in comparison to that without the S 3 M process. This work provides a facile and efficient strategy for solid-state and high-value utilization of biomass materials, for which the traditional processing approaches encounter challenges on a large scale.

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“…According to ReforceTech AS Company, the MiniBars™ contain 80% basalt fiber and 20% resin, and their density is around 2.1 g/cm 3 . The degree of crystallinity for fly ash and geopolymer from X-ray diffraction from previous work [ 6 ] was calculated as the ratio between the area of the diffraction peaks due to the crystalline phases, divided by the sum of the diffraction areas due to the crystalline phases, plus the areas coming from the halos of the amorphous phases, using Equation (1) [ 15 ]: D cr = (I c )/(I c + I a ) where D cr is the degree of crystallinity, I c is the sum of the areas from the crystalline phases in the sample and I a is the area due to the halos from the amorphous phases.…”

Section: Methodsmentioning

confidence: 99%

Mechanical Properties of MiniBars™ Basalt Fiber-Reinforced Geopolymer Composites

Furtos,

Prodan,

Sarosi

et al. 2024

Materials

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Fly ash-based geopolymers represent a new material, which can be considered an alternative to ordinary Portland cement. MiniBars™ are basalt fiber composites, and they were used to reinforce the geopolymer matrix for the creation of unidirectional MiniBars™ reinforced geopolymer composites (MiniBars™ FRBCs). New materials were obtained by incorporating variable amount of MiniBars™ (0, 12.5, 25, 50, 75 vol.% MiniBars™) in the geopolymer matrix. Geopolymers were prepared by mixing fly ash powder with Na2SiO3 and NaOH as alkaline activators. MiniBars™ FRBCs were cured at 70 °C for 48 h and tested for different mechanical properties. Optical microscopy and SEM were employed to investigate the fillers and MiniBars™ FRBC. MiniBars™ FRBC showed increasing mechanical properties by an increased addition of MiniBars™. The mechanical properties of MiniBars™ FRBC increased more than the geopolymer wtihout MiniBars™: the flexural strength > 11.59–25.97 times, the flexural modulus > 3.33–5.92 times, the tensile strength > 3.50–8.03 times, the tensile modulus > 1.12–1.30 times, and the force load at upper yield tensile strength > 4.18–7.27 times. SEM and optical microscopy analyses were performed on the fractured surface and section of MiniBars™ FRBC and confirmed a good geopolymer network around MiniBars™. Based on our results, MiniBars™ FRBC could be a very promising green material for buildings.

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Methods of determining the degree of crystallinity of polymers with X-ray diffraction: a review

Cited by 11 publications

References 280 publications

Cross-Linking Synergistic Effects to Enhance the Comprehensive Properties of Electrospun Polyimide Nanofiber Membranes for Advanced Lithium-Ion Batteries

Cross-Linking Synergistic Effects to Enhance the Comprehensive Properties of Electrospun Polyimide Nanofiber Membranes for Advanced Lithium-Ion Batteries

Solid-State Utilization of Chitin to Construct Flexible Films with Enhanced Biocompatibility and Mechanical Performance

Mechanical Properties of MiniBars™ Basalt Fiber-Reinforced Geopolymer Composites

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