Effects of crystallization temperature and spherulite size on cracking behavior of semi-crystalline polymers

Zhang, Chaowen; Lu, Lu; Li, Wenqiang; Li, Lihua; Zhou, Changren

doi:10.1007/s00289-016-1634-2

Cited by 14 publications

(5 citation statements)

References 37 publications

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“…It seems the addition of FD-TMCNC suppressed the growth of inhomogeneous large spherulites and contributed to the increase in elasticity of the composite, promoting fast crystallization. According to the literature, such fast crystallization of the polymer results in a smaller average size of spherulite, and composites with such small spherulites show better mechanical performances than larger spherulite-containing composites [51][52][53]. Thus, in this study, we assumed that 5% of FD-TMCNCs plays a similar role as nucleating agents in PHA.…”

Section: Thermal Behaviors Of the Pha/5% Fd-tmcncs Compositementioning

confidence: 99%

“…A peak of T m1 (106-119 • C) and exothermic cold crystallization peaks (T c*1 , 60-100 • C) appeared in the pristine PHA, while they were negligible in the CNCs containing counterpart. The increase of T c may have been associated with the increase of crystalline regions, crack density, and spherulite sizes, and consequently the brittleness of the polymer [51]. The presence of two melting peaks (T m1 and T m2 ) in the pristine PHA implied the inhomogeneous growth of crystals, as T m1 is attributed to the melting of the primary crystals and T m2 to the melting of crystals from recrystallization [52].…”

Section: Thermal Behaviors Of the Pha/5% Fd-tmcncs Compositementioning

confidence: 99%

“…Such a microstructure can lead to a decrease of ductility of amorphous pristine PHA. Zhang et al [51] reported that a decrease in radius of spherulites results in a reduction of cracks in spherulites and an increase of elasticity of PHA. According to the results above, it is assumed that the pristine PHA composite formed by the melt-extrusion process had relatively more crystalline regions with inhomogeneous crystal growth, which made it less ductile compared to the PHA/5% FD-TMCNCs.…”

Section: Thermal Behaviors Of the Pha/5% Fd-tmcncs Compositementioning

confidence: 99%

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Changes in Mechanical Properties of Polyhydroxyalkanoate with Double Silanized Cellulose Nanocrystals Using Different Organosiloxanes

Kim

Jeong

et al. 2021

Nanomaterials

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Polyhydroxyalkanoate (PHA) is a biodegradable plastic with great potential for tackling plastic waste and marine pollution issues, but its commercial applications have been limited due to its poor processability. In this study, surface-modified cellulose nanocrystals were used to improve the mechanical properties of PHA composites produced via a melt-extrusion process. Double silanization was conducted to obtain hydrophobically treated CNC-based fillers, using tetraethyl orthosilicate (TEOS) and methyltrimethoxysilane (MTMS). The morphology, particle size distributions, and surface characteristics of the silanized CNCs and their compatibility with a PHA polymer matrix differed by the organosiloxane treatment and drying method. It was confirmed that the double silanized CNCs had hydrophobic surface characteristics and narrow particle size distributions, and thereby showed excellent dispersibility in a PHA matrix. Adding hydrophobically treated CNCs to form a PHA composite, the elongation at break of the PHA composites was improved up to 301%, with little reduction of Young’s modulus, compared to pure PHA. Seemingly, the double silanized CNCs added played a similar role to a nucleation agent in the PHA composite. It is expected that such high ductility can improve the mechanical properties of PHA composites, making them more suitable for commercial applications.

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Section: Thermal Behaviors Of the Pha/5% Fd-tmcncs Compositementioning

confidence: 99%

Section: Thermal Behaviors Of the Pha/5% Fd-tmcncs Compositementioning

confidence: 99%

Section: Thermal Behaviors Of the Pha/5% Fd-tmcncs Compositementioning

confidence: 99%

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Changes in Mechanical Properties of Polyhydroxyalkanoate with Double Silanized Cellulose Nanocrystals Using Different Organosiloxanes

Kim

Jeong

et al. 2021

Nanomaterials

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“…Furthermore, the melting range in all three aging stages in the bottom two graphs is significantly lower compared to that of the unaged sheets. This can be attributed to the changes in crystal distribution, particularly the further growth of thicker lamellae and melting of thinner lamellae during the aging test, and the lack of notable distinction among the samples may be due to the disruption caused by damage to network molecules [22]. After the heat treatment, both the unaged and 60-day-aged sheets exhibit a similar trend: higher crystallinity is achieved at higher heat treatment temperatures, accompanied by a decrease in the melting range.…”

Section: Heat Treatment On Xlpe Sheetsmentioning

confidence: 99%

Experimental Study on Rejuvenation of Aged Power Cables via Simulation Operation

Xie,

Zhang,

Lou

et al. 2024

Energies

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Thermal effects play a crucial role in the evolution of insulation performance in power cables during long-term operation. Before the experiments, crosslinked polyethylene (XLPE) sheets and cables were thermally aged at 105 °C for up to 180 days. Then, the heat treatments on XLPE sheets and cables were conducted in three stages. Firstly, the aged sheets were subjected to heat treatment with a temperature range of 90 to 115 °C at intervals of 5 °C, with each step lasting for 20 h. Secondly, a 7-year-serviced cable underwent simulated cable operation at the same temperature as the XLPE sheets. Thirdly, two 15- and 30-year-serviced cables were treated at temperatures ranging from 90 to 105 °C, adhering to the same intervals as the second stage. The differential scanning calorimetry (DSC), cross-linking degree, DC conduction, and breakdown strength were measured. The results show that both heat treatment methods are effective in enhancing crystallization characteristics and conductivity for XLPE sheets and aged cables, and the optimum values were achieved at decreasing temperatures as the aging period extended. Moreover, the heat treatment on retired cables yielded similar results, suggesting that a heat treatment resembling cable operation at higher temperatures would initially be beneficial for cable rejuvenation.

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“…So far, many methods have been used to obtain partial information about the organization of micro- and nanomaterials. These include X-ray diffraction, electron microscopy, and atomic force microscopy . Several polymers were found to show changes in IR and/or Raman spectra depending on the crystallization process, which influenced the size and shape of crystal forms. ,,− The effects of the morphology, conformation, and configuration on the spectra were studied by many groups.…”

Section: Introductionmentioning

confidence: 99%

Insight into Poly(l-lactic acid) Coexisting Amorphous and Semicrystalline Phases Using FT-IR Imaging and Four Polarization-Three Dimensional Macromolecular Orientation Calculation

Kosowska,

Koziol,

Roman

et al. 2024

Macromolecules

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A recently developed concurrent analysis of fourpolarization IR (4P) data offers retrieval of three-dimensional (3D) orientation angles of macromolecules. Since it has only been for highly structured samples, it is important to explore its capabilities in samples lacking structure. Therefore, the nondestructive and label-free four polarization methodology was used to image the 3D orientation angles (4P-3D) and order parameters in different regions of anisotropic poly(L-lactic acid) thin film with coexisting amorphous and crystalline phases. The results show the variety of macromolecule three-dimensional organization in different types of polymer structures: the single circular spherulite, neighboring spherulites, and the amorphous phase. The arrangement of the chains and the degree of deviation from the normal of the film vary, depending on the morphology of the polymer film.

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Effects of crystallization temperature and spherulite size on cracking behavior of semi-crystalline polymers

Cited by 14 publications

References 37 publications

Changes in Mechanical Properties of Polyhydroxyalkanoate with Double Silanized Cellulose Nanocrystals Using Different Organosiloxanes

Changes in Mechanical Properties of Polyhydroxyalkanoate with Double Silanized Cellulose Nanocrystals Using Different Organosiloxanes

Experimental Study on Rejuvenation of Aged Power Cables via Simulation Operation

Insight into Poly(l-lactic acid) Coexisting Amorphous and Semicrystalline Phases Using FT-IR Imaging and Four Polarization-Three Dimensional Macromolecular Orientation Calculation

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