Article
Polymer Science
Lidong Feng, Xinchao Bian, Gao Li, Xuesi Chen
Summary: By investigating the thermal properties, morphology, and thermal stability of PLLA/PDLA blends, a new stereoamorphous mesophase (sam-PLA) structure was discovered, and the relationship between different phases in the PLLA/PDLA blends was explored.
Article
Polymer Science
Mingmei Mi, Jing Yu, Xiangyang Li, Min Zhou, Hao Xiu, Hongwei Bai
Summary: Stereocomplex-type polylactide (SC-PLA) is a promising engineering bio-plastic that enhances heat resistance and hydrolytic stability through the crystallization between poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA). By using dibenzoylhydrazide compound as a nucleating agent, the SC crystallization of PLLA/PDLA blends is promoted, leading to smaller crystal size.
Article
Polymer Science
Wenze Li, Mengyao Wang, Huan Luo, Yanhua Niu, Yajiang Huang, Guangxian Li
Summary: This study investigates the crystallization behaviors of stereocomplex and homochiral crystals by blending high molecular weight PLLA with low molecular weight PDLA and its diblock copolymers. It was found that the introduction of different sequences can inhibit the crystallization kinetics of the blends, with the formation of sc crystalites prior to hc ones. Additionally, micro phase separation between PLA and PDMS segments was observed to weaken the competition between sc and hc crystals.
Article
Polymer Science
Lidong Feng, Xinchao Bian, Gao Li, Xuesi Chen
Summary: The study shows that the compatibility between PLLA and PLDLA-m decreases as the L-lactate unit content in PLDLA-m decreases, impacting the crystallization and compatibility of the blends.
Article
Polymer Science
Suyang Dai, Ziming Dai, Ni Jiang, Zhenbo Ning, Zhihua Gan
Summary: In this study, poly(L-lactide) (PLLA) was toughened by crosslinked polyurethane (CPU) through reactive blending. The resulting material exhibited significant increase in elongation at break, enhanced toughness, and shape memory capacity, showing great potential for applications in biodegradable green composites.
Article
Biotechnology & Applied Microbiology
Tiantang Fan, Jingwen Qin, Xiao Meng, Jiafeng Li, Qing Liu, Guannan Wang
Summary: PLPG membranes with sc-PLA improved the crystallizing behavior of PLLA segments, increased thermal stability and degradation ability, and showed low cytotoxicity.
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
(2022)
Article
Polymer Science
Suyang Dai, Ni Jiang, Zhenbo Ning, Zhihua Gan
Summary: The length of the PDLA block was found to have a significant impact on the degradation behavior of PLLA/4-DL-D blend films.
POLYMER INTERNATIONAL
(2021)
Article
Biochemistry & Molecular Biology
Wei-Wei Chang, Jinye Niu, Hui Peng, Weifeng Rong
Summary: In this study, selective formation of stereocomplex (sc) crystallization and suppression of homocrystallization (hc) in high-molecular-weight (HMW) PLLA/PDLA blends were achieved by adding C70 as a nucleator. Fourier-transformed infrared spectroscopy analysis revealed improved intermolecular interactions and inhibited molecular chain diffusion and mobility, leading to accelerated sc crystallization. The addition of C70 also resulted in a higher thermal stability compared to the neat PLLA/PDLA blend.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2023)
Article
Chemistry, Multidisciplinary
N. M. Praveena, Selvaraj Nagarajan, E. Bhoje Gowd
Summary: The cooling rate from the melt significantly influences the formation of stereocomplexes in equimolar blends of enantiomeric star-shaped poly(lactide)s with a dipyridamole core. Fast cooling leads to non-aggregated core molecules and antiparallel chain packing, favoring the formation of stereocomplexes, while slow cooling results in topological and geometric constraints due to possible core molecule aggregation, inhibiting crystallization of the poly(lactide) chains.
Article
Materials Science, Multidisciplinary
Vipin G. Krishnan, N. M. Praveena, R. B. Amal Raj, Kiran Mohan, E. Bhoje Gowd
Summary: In this study, a facile strategy was reported to enhance the thermal and mechanical properties of polylactide (PLA) aerogels through stereocomplexation. The crystalline pure stereocomplex (SC) aerogels showed improved melting temperature, thermal stability, mechanical strength, and sound absorption ability compared to homopolymer aerogels.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Crystallography
Xingyuan Diao, Xiaonan Chen, Shihao Deng, Hongwei Bai
Summary: In this study, trace amounts of epoxy-functionalized small-molecule modifiers were introduced into enantiomeric blends during reactive melt-blending to enhance the formation of stereocomplex-type polylactide (SC-PLA). The results showed that the in situ generation of multi-arm stereo-block PLA copolymers significantly improved SC formation, even with only 0.5 wt% modifiers. The unique copolymers acted as compatibilizers, suppressing the separation of the alternately arranged PLLA/PDLA chain segments in the molten state. Furthermore, the generation of these copolymers did not significantly increase the melt viscosity of the blends, suggesting new opportunities for high-throughput processing of SC-PLA materials.
Article
Polymer Science
Hideto Tsuji, Kazumasa Iguchi, Yuki Arakawa
Summary: The research studied the effects of different molecular weights of crystalline blocks but similar overall molecular weights on the crystallization behavior, structure, morphology, and thermal properties of PLLA-b-PDLLA/PDLA-b-PDLLA blends. It was found that the incorporated long amorphous PDLLA blocks facilitated unique SC crystallization in the blends with different crystalline block fractions.
Article
Polymer Science
Qianjin Zhu, Kaixin Chang, Liyan Qi, Xinyi Li, Woming Gao, Qinwei Gao
Summary: In this study, PLLA films were surface-modified using different solutions, leading to changes in their structure and properties. The modification with PDLA weakened the crystal structure of the films, while modification with PDLAG increased the stereocomplex (SC) structure and decreased the homogeneous crystal (HC) structure.
Article
Polymer Science
Yodthong Baimark, Prasong Srihanam, Yaowalak Srisuwan, Theeraphol Phromsopha
Summary: The stereocomplex polylactide (scPLA) powder showed great potential as an effective nucleating agent for improving the crystallization properties of high-molecular-weight poly(L-lactide) (HMW-PLLA) bioplastic.
Article
Polymer Science
Martin Boruvka, Cenek Cermak, Lubos Behalek, Pavel Brdlik
Summary: This study focused on characterizing the properties of nanocomposite systems based on asymmetric poly(L-lactide)/Poly(D-lactide) blends with the addition of nano-hydroxyapatite (HA) and 5 wt.% PDLA loading. The results showed that increasing HA content and blending with 5 wt.% PDLA enhanced tensile modulus, crystallinity, and thermal-resistance, while in-mold annealing further improved these properties by achieving a higher degree of crystallinity. However, higher HA content and in-mold annealing resulted in decreased % elongation values at break and tensile strength, as well as caused embrittlement of the material systems.
Article
Chemistry, Physical
Yuki Arakawa, Kenta Komatsu, Takuma Shiba, Hideto Tsuji
Summary: This study synthesized a series of classic LC trimer homologs and reevaluated their elusive monotropic mesophases, revealing the novel heliconical NTB phase in achiral bent molecules. The alternating induction of Sm and NTB phases depending on n parity was only observed in LC trimer homologs, suggesting steric interactions play a crucial role in determining the mesophase behavior.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Multidisciplinary
Yuki Arakawa, Yuko Ishida, Takuma Shiba, Kazunobu Igawa, Shunsuke Sasaki, Hideto Tsuji
Summary: The alkylthio groups mainly decrease phase transition temperatures, especially T-NI or T-IN, and hinder liquid crystal formation for organic rod-like molecules, primarily due to conformational flexibility, steric bulkiness, and lower molecular anisotropy imposed by C-S-C. The sulfur atom contributes to intermolecular attractive interactions, reflected in phase transitions as spatially averaged phenomena (i.e., dispersion force and more polarizable pi-systems). The influence of these interactions becomes more pronounced with lengthening alkyl chains.
Article
Chemistry, Physical
Marta Pytlarczyk, Jakub Herman, Yuki Arakawa, Hideto Tsuji, Przemyslaw Kula
Summary: Liquid crystals, especially those with high birefringence, are crucial in optoelectronic devices, but their lifetime is affected by photodegradation processes. New reinforced molecules and deuterated liquid crystals show higher photochemical stability and isotopic purity, indicating potential for widespread use in various liquid crystal devices.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Polymer Science
Hideto Tsuji, Sena Nogata, Hirotada Gamo, Kazuhiro Hikima, Atsunori Matsuda, Yuki Arakawa
Summary: This study investigated enantiomeric aromatic poly(lactic acid)s and their crystallization, thermal properties, and degradation. It was found that high molecular weight poly(L-mandelic acid) and poly(d-mandelic acid) exhibited predominant stereocomplex crystallization, while low molecular weight blends showed both stereocomplex and homo-crystallization. The aromatic poly(mandelic acid) had higher glass transition temperatures and lower melting temperatures compared to previously reported poly(lactic acid)s. The thermal degradation temperatures of the blends were higher than those of enantiomeric poly(lactic acid)s and similar to enantiomeric poly(2-hydroxybutanoic acid)s. The study also compared the crystallizability of aromatic poly(mandelic acid) and poly(phenyllactic acid).
POLYMER DEGRADATION AND STABILITY
(2022)
Correction
Chemistry, Multidisciplinary
Hideto Tsuji, Kazuya Nakayama, Yuki Arakawa
Summary: This article presents a study on the synthesis of poly(lactic acid-alt-2-hydroxybutanoic acid) copolymers with two types of chiral centers, as well as the correction for errors in the study.
Article
Crystallography
Yuki Arakawa, Kenta Komatsu, Hideto Tsuji
Summary: In this study, we report the synthesis, phase-transition behaviour, and mesophase structure of fluorenone-incorporated LC trimers that exhibit an emerging helical twist-bend nematic (N-TB) phase. These LC trimers have a central 2,7-ether-substituted fluorenone and bilateral cyanobiphenyl groups linked via odd alkylene spacers, and they are important for the research of organic liquid crystals.
Article
Chemistry, Physical
Yuki Arakawa, Kenta Komatsu, Yuko Ishida, Takuma Shiba, Hideto Tsuji
Summary: We report the synthesis, phase-transition behavior, and mesophase structures of the first series of thioether-linked liquid crystal trimers. The results showed that even-n and odd-n homologs exhibited different LC phases, which is attributed to the different average molecular shapes associated with the relative orientations of the biphenyl moieties. X-ray diffraction analysis indicated a strong cybotactic phase tendency, and the thioether linkages endowed the trimers with a monotropic LC tendency and lowered phase-transition temperatures compared to all-ether-linked trimers.
Article
Polymer Science
Hideto Tsuji, Katsuya Osanai, Yuki Arakawa
Summary: Asymmetric combinations of chiral 2-hydroxyalkanoic acid-based random copolymers with different configurations were found to form stereocomplex crystallites, expanding the properties and biodegradation behavior of this type of polymer materials.
Article
Polymer Science
Hideto Tsuji, Sena Nogata, Narumi Tsukamoto, Yuki Arakawa
Summary: The effects of incorporating PDLLA and solvent on SC crystallization and homocrystallization of PLLA and PDLA chains were investigated. The presence of PDLLA and solvent increased SC crystallinity and total crystallinity, while decreasing homocrystallinity.
Article
Chemistry, Multidisciplinary
Marta Pytlarczyk, Jakub Herman, Michal Czerwinski, Yuki Arakawa, Hideto Tsuji, Przemyslaw Kula
Summary: This paper introduces a method for synthesizing deuterated liquid crystals using a continuous flow system, and demonstrates through experiments and theoretical calculations that deuterium-labeled liquid crystals exhibit increased photochemical stability. The physical and chemical properties of deuterated and non-labeled liquid crystals are also compared.
Article
Chemistry, Physical
Satoshi Aya, Wentao Tang, Xian Kong, Yuki Arakawa, Kenta Komatsu, Hideto Tsuji
Summary: This study reports the ultraslow electric-driven dynamics in bent-shaped nematic materials, with significantly higher on/off-switching time and threshold voltage for inducing reorientation compared to traditional materials. These properties are discussed in terms of dielectric constants and electrohydrodynamic convection.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Crystallography
Yuki Arakawa, Yuto Arai, Kyohei Horita, Kenta Komatsu, Hideto Tsuji
Summary: This study investigates the effects of different linkage types on the phase-transition behaviors of cyanobiphenyl dimers, revealing their influence on the transition temperature and crystallization tendencies. The findings highlight the characteristics of liquid crystal phase transitions.
Article
Chemistry, Multidisciplinary
Yuki Arakawa, Takuma Shiba, Kazunobu Igawa, Shunsuke Sasaki, Hideto Tsuji
Summary: This study reports the synthesis and phase-transition behavior of a new series of 4'-alkylseleno-4-cyanobiphenyls. It was found that compounds with shorter alkyl chain lengths displayed a monotropic nematic phase at low temperatures, while those with longer alkyl chain lengths formed N phases. The length of the alkyl chain had a significant impact on the phase-transition temperatures. Furthermore, compared to other homologous series, the 4'-alkylseleno-4-cyanobiphenyls showed lower mesogenic ability and lower phase-transition temperatures.
Article
Materials Science, Multidisciplinary
Hideto Tsuji, Narumi Tsukamoto, Yuki Arakawa
Summary: In this study, PLLA films were coated with different block copolymers to achieve controlled surface properties and hydrolytic degradation rates. The coatings successfully altered the hydrophilicity or hydrophobicity of the PLLA films, and the coated materials showed decelerated hydrolytic degradation. The PLLA-PB-PLLA coating exhibited higher resistance to hydrolytic degradation and longer-lasting hydrophobization effects compared to the PLLA-PEG-PLLA coating.
MATERIALS ADVANCES
(2022)
Article
Materials Science, Multidisciplinary
Yuki Arakawa, Yuko Ishida, Yukito Sasaki, Shunsuke Sasaki, Masatoshi Tokita, Hideto Tsuji
Summary: This study investigated the effects of alkylthio and alkoxy groups on short-chain liquid crystal phases. A novel series of asymmetric 1,4-phenylene bis(benzoate)s were synthesized, and it was found that the compound with the shortest chain length formed a unique half-intercalated liquid crystal phase. X-ray diffraction results showed that the layer period of this phase was half of the molecular length.
MATERIALS ADVANCES
(2022)
Article
Polymer Science
Tetsu Sato, Mariko Takahashi, Takeshi Saito, Masahito Toyonaga, Itsuo Tanuma, Rie Yamada, Satoru Hosoda
Summary: An automatic evaluation system for photooxidation has been developed and successfully applied to assess the photo-OIT of LDPE samples containing photooxidation stabilizers. The system allows independent setting of various measurement conditions and provides detailed information on the photooxidation process.
POLYMER DEGRADATION AND STABILITY
(2024)
Article
Polymer Science
Zongzheng Zuo, Shuxue Zhou
Summary: In this study, three fluoroalkyl trimethoxysilane (FATMS) additives with different chain lengths were incorporated into a two-component polyurethane clearcoat to improve its hydrophobic durability. The coatings modified with FATMS maintained their surface hydrophobicity under various conditions, but quickly lost it when exposed to both UV irradiation and/or high temperature with water. The results suggest that the FATMS route is more suitable for indoor applications at room temperature.
POLYMER DEGRADATION AND STABILITY
(2024)
Article
Polymer Science
Song Li, Feng Zhao, Xueya Wang, Zhihua Liu, Jingze Guo, Yutong Li, Shuangmei Tan, Zhenxiang Xin, Shuai Zhao, Lin Li
Summary: Green flame retardants have garnered attention for their environmental friendliness, but current options fall short in achieving high flame retardancy for flammable polymers and maintaining environmental protection. This study takes a two-pronged approach to address flame retardants and the flame-retardant process. An eco-friendly bio-based synergistic flame retardant (PAU), synthesized using phytic acid (PA) and urea (U), is used to create a flame retardant coating that can be directly applied to any surface shape using polydopamine as an adhesive. The resulting EPS-PAU exhibits excellent flame retardancy, smoke suppression, and light weight while only slightly increasing the density.
POLYMER DEGRADATION AND STABILITY
(2024)
