Polymer Degradation and Stability最新文献

英文中文

Favorable compatibility efficiency and thermal stability of PLA/P4HB/PGMA blends contributed by phase interface-located chain expansion reaction

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111159

Yitong Ding , Mingjiao Li , Wenjing Dong, Ze Kan, Zhibo Li

Chemically synthesized poly(4-hydroxybutyrate) (P4HB) serves as an alternative material for toughening poly(lactic acid) (PLA), but the two materials exhibit poor compatibility, and most compatibilizers fail to localize at the phase interface, resulting in inefficient toughening. In this study, a phase interface-located reactive compatibilizer, poly (glycidyl methacrylate) (PGMA), is synthesized to enhance the interfacial adhesion between PLA and P4HB, thereby improving their compatibility. The PGMA compatibilizer demonstrates a tendency to selectively disperse at the phase interface of PLA and P4HB supported by thermodynamic calculations. Compared to the PLA/P4HB blend, the PLA/P4HB/PGMA blend exhibits enhanced molecular chain entanglement and a blurrier phase interface. Consequently, the mechanical and shape memory behavior of the PLA/P4HB/PGMA blend are improved. For example, the elongation at break of the PLA/P4HB/PGMA blend increased from 20.8 % to 265.1 %, marking an increase of 12.7 times compared to the PLA/P4HB blend. Due to its small molecular weight, the

T_{o n e s e t}

(onset degradation temperature) of PGMA is only 180.3 °C. Fortunately, the

T_{o n e s e t}

of the PLA/P4HB/PGMA system exceeds 220 °C after the chain expansion reaction, indicating a significant improvement in thermal stability. Thus, the phase interface-located chain expansion reaction offers an effective approach to improving the compatibility of PLA/P4HB blends while maintaining their high thermal stability.

化学合成的聚（4-羟基丁酸）（P4HB）可作为聚乳酸（PLA）增韧的替代材料，但这两种材料的相容性较差，而且大多数相容剂无法在相界面定位，导致增韧效率低下。本研究合成了一种位于相界面的反应性相容剂--聚（甲基丙烯酸缩水甘油酯）（PGMA），以增强聚乳酸和 P4HB 之间的界面粘附力，从而提高它们的相容性。根据热力学计算，PGMA 相容剂在聚乳酸和 P4HB 的相界面上有选择性分散的趋势。与聚乳酸/P4HB 共混物相比，聚乳酸/P4HB/PGMA 共混物表现出更强的分子链缠结和更模糊的相界面。因此，聚乳酸/P4HB/PGMA 混合物的机械和形状记忆性能得到了改善。例如，聚乳酸/P4HB/PGMA 混合物的断裂伸长率从 20.8% 提高到 265.1%，与聚乳酸/P4HB 混合物相比提高了 12.7 倍。由于分子量较小，PGMA 的起始降解温度（Toneset）仅为 180.3 °C。幸运的是，聚乳酸/P4HB/PGMA 体系在发生扩链反应后的温度起始值超过了 220 °C，这表明其热稳定性有了显著提高。因此，相界面定位链膨胀反应为提高聚乳酸/P4HB 混合物的相容性并保持其较高的热稳定性提供了一种有效的方法。

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引用次数: 0

Alcohol degradation of anhydride-cured epoxy resin insulations and the properties of recycled materials 酸酐固化环氧树脂绝缘材料的酒精降解和再生材料的性能

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111134

Xu Zhang , Yiran Hu , Guoli Wang , Chao Gao , Jiahe Yu , Xiaoxing Zhang , Yunjian Wu

Epoxy resins are widely used as electrical insulation materials due to their excellent properties. However, the three-dimensional network structure of epoxy resin makes it difficult to be degraded and recycled, and incineration or landfill will cause environmental pollution as well as waste of resources. In order to study the degradation technology of epoxy insulating materials (EIM) under mild conditions, the degradation of EIM was achieved under mild conditions using K₃PO₄ as a catalyst in ethylene glycol at 120 °C for 3 h Degradation products of epoxy resin insulation materials (DEM) were used to partially replace bisphenol A diglycidyl ether (DGEBA) in the preparation of recycled epoxy resin insulation materials (RIM). The results showed that RIM could maintain good insulating properties when the DEM content was lower than 38.4 wt.%, the tensile strength and T_g were also held up will when the DEM content was 22wt.%. This study provides new ideas and methods for the recycling of epoxy resin insulating materials, which can help the resourceful reuse of epoxy cast electrical equipment after decommissioning.

环氧树脂因其优异的性能而被广泛用作电绝缘材料。然而，环氧树脂的三维网状结构使其难以降解和回收，焚烧或填埋会造成环境污染和资源浪费。为了研究环氧绝缘材料（EIM）在温和条件下的降解工艺，以K3PO4为催化剂，在乙二醇中120℃下反应3h，在温和条件下实现了EIM的降解。采用环氧树脂保温材料（DEM）降解产物部分取代双酚A二缩水甘油酯醚（DGEBA）制备再生环氧树脂保温材料（RIM）。结果表明，当DEM含量低于38.4 wt.%时，RIM仍能保持良好的绝缘性能，当DEM含量为22wt.%时，RIM的抗拉强度和Tg也保持不变。本研究为环氧树脂绝缘材料的回收利用提供了新的思路和方法，有助于环氧铸造电气设备退役后的资源化再利用。

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引用次数: 0

Impact of phosphonate and phosphoramidate in Si/P/triazine hybrid flame retardants on cotton flammability

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111107

Valbone Shabani , Wael Ali , Bassem Assfour , Raphael Otto , Dennis Killa , Seden Caglar , Ying Feng , Eui-young Shin , Jochen S. Gutmann , Thomas Mayer-Gall

Phosphorus and nitrogen-containing flame retardants are well-known for their high efficacy when used in combination, either as separate compounds or within the same molecule. However, a detailed examination of the chemical bonding of phosphorus is needed to understand the flame behavior. To this end, two different scenarios were examined and compared with a phosphorus-free benchmark. Both scenarios contain a triazine ring and a silane-based precursor. The first scenario involves a direct bond between phosphorus and triazine (phosphonate), while the second involves a bridging of phosphorus and triazine via nitrogen (phosphoramidate). This allowed to investigate the structural effect of phosphoramidate and phosphonate of triazine derivatives on the thermal and flame retardant behavior. The flame-retardant performance and mechanism of the treated samples were investigated by means of the vertical flame test (DIN EN ISO 15025), thermogravimetric analysis and microscale combustion calorimetry, amongst others. Our research shows that triazine-based phosphonate has a better flame retarding effect on cotton than phosphoramidate at the same phosphorus concentration. Self-extinguishing characteristics was observed at a low add-on value of 0.23 mmol/g for phosphonate-based flame retardant, while a higher add-one value of 0.24 mmol/g was required in the case of phosphoramidate. The comprehensive analysis demonstrated that both flame retardants undergo mechanisms in both the gas phase and condensed phase by releasing incombustible gases and promoting the carbonization of cotton fabrics.

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引用次数: 0

Construction of durable biomass-based flame retardant with high phosphorus and nitrogen contents for wood coatings

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111160

An Wei , Shunxiang Wang , Xulan Lu , Yongjin Zou , Cuili Xiang , Fen Xu , Lixian Sun , Yunhao Lu

As a commonly used material, wood's inherent flammability poses a significant fire safety hazard to people, and it is necessary to improve the flame-retardant performance of wood. This study prepared a novel lignin-based intumescent flame-retardant (PGL) using phosphorus-rich phytic acid, nitrogen-rich guanazole, and carbon-rich lignin as raw materials. Subsequently, PGL was infiltrated into the urea-formaldehyde resin as a flame-retardant component, and a series of PGL-modified urea-formaldehyde resin wood coatings (PGLUF) were prepared. The wood coated with PGLUF exhibited high flame retardancy and passed the UL-94 V-0 level test with a limit of oxygen index (LOI) of 36.5 %. The total heat release (THR) and peak heat release rate (PHRR) were reduced by 92.73 % and 93.58 %, respectively, compared to pure wood. Moreover, when the PGL content was 3 wt.%, the PGLUF could achieve comparable flame retardancy to the coating containing 5 wt.% commercial flame-retardant (triphenyl phosphate, TPP). PGL also exhibited a plasticizing effect on the coatings. The impact strength of PGLUF-coated wood increased with the increase of PGL content. PGL can simultaneously enhance the flame retardancy and mechanical properties of materials, and the preparation process is green and safe. Therefore, the PGL shows excellent potential in practical applications.

木材作为一种常用材料，其固有的易燃性给人们带来了极大的消防安全隐患，因此有必要提高木材的阻燃性能。本研究以富含磷的植酸、富含氮的胍唑和富含碳的木质素为原料，制备了一种新型木质素基膨胀型阻燃剂（PGL）。随后，将 PGL 作为阻燃成分渗入脲醛树脂中，制备出一系列 PGL 改性脲醛树脂木涂料（PGLUF）。涂有 PGLUF 的木材具有很高的阻燃性，通过了 UL-94 V-0 级测试，氧指数（LOI）为 36.5%。与纯木材相比，总放热量（THR）和峰值放热率（PHRR）分别降低了 92.73 % 和 93.58 %。此外，当 PGL 含量为 3 wt.%时，PGLUF 的阻燃性能与含 5 wt.% 商用阻燃剂（磷酸三苯酯，TPP）的涂层相当。PGL 还对涂层具有增塑作用。PGLUF 涂层木材的冲击强度随着 PGL 含量的增加而增加。PGL 可同时提高材料的阻燃性和机械性能，而且制备过程绿色安全。因此，PGL 在实际应用中显示出巨大的潜力。

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引用次数: 0

Enhancing flame-retardant and mechanical properties of epoxy composites through bio-based flame retardant treated cotton fabric reinforcement 通过生物基阻燃处理棉织物增强环氧树脂复合材料的阻燃性和机械性能

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111109

Maksym Li , Prabhakar M．N． , Jong-kyu Park , Jung-il Song

Due to tightening fire safety regulations and environmental concerns, eco-friendly natural fiber-reinforced composites (NFRCs) are increasingly popular for their biodegradability, renewability, low cost, and high specific mechanical properties. However, ensuring fire safety in NFRCs is challenging, as conventional synthetic flame retardants can reduce mechanical properties due to particle agglomeration and poor compatibility with the matrix. Therefore, in this study, the flame-retardant epoxy composite (EP/FR) was fabricated by using cotton treated with novel dual complex solutions containing phytic acid, chitosan, and urea. Remarkably, applying just one bilayer of this treatment led to significant improvements in flame retardancy, as evidenced by a reduction of up to 44.8 % in the peak heat release rate and a 23.7 % decrease in total heat release during cone calorimeter testing. Additionally, the horizontal burning rate was reduced by up to 16.8 %. Analysis of solid residue after fire test and gas product liberated during pyrolysis demonstrated an intumescent mechanism of flame retardancy. Mechanical property studies showed better performance for EP/FR, with SEM of the fractured surface proving better interfacial adhesion between fiber and matrix because of the fiber treatment. Overall, this study offers a novel and greener approach to improving the flame-retardant and mechanical properties of NFRC, paving the way for more sustainable composite materials.

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引用次数: 0

Raman spectroscopic observation of conformational changes during thermal exposure and its effects on melting and crystallization behavior of high-density polyethylene 拉曼光谱观测热暴露期间的构象变化及其对高密度聚乙烯熔化和结晶行为的影响

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111152

Yusuke Hiejima , Hikaru Kawada , Takumitsu Kida , Koh-hei Nitta

In the present study, we used Raman spectroscopy to reveal conformational changes of high-density polyethylene (HDPE) during long-time thermal exposure in air at 110 °C. In the early stage, we observed an increase in crystallinity complemented by a decrease in the number of non-crystalline short trans sequences owing to structural rearrangement, which is the typical effect of annealing. Deterioration of the mechanical properties, such as a decrease in the strain at break, gradually proceeded, even before chemicrystallization. This will be ascribed to conformational reordering of the crystalline structure, i.e., a gradual increase in crystallinity accompanied by a decrease in both non-crystalline short and long trans sequences. During chemicrystallization, a further increase of crystallinity accompanied by elimination of the non-crystalline short and long trans sequences resulted in embrittlement of the HDPE specimen. Conformational changes in the HDPE specimen after thermal exposure were monitored in situ during heating and cooling. The trans sequence formed during thermal exposure was highly stabilized, resulting in higher crystallinity and trans fractions up to the vicinity of the melting temperature. The detection of non-crystalline short trans sequences can be used to predict the degree of deterioration of thermally exposed HDPE owing to the strong correlation between the decrease in the number of non-crystalline short trans sequences and the strain at break.

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引用次数: 0

Preparation of perovskite catalysts and their mechanism of catalytic degradation and regeneration of waste polyisocyanurate 过氧化物催化剂的制备及其催化降解和再生废弃聚异氰脲酸酯的机理

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111138

Xiaohua Gu , Shangwen Zhu , Siwen Liu , Chin Hao Chong

Polyisocyanurate (PIR) foam is a modified polyurethane material that is a waste containing highly cross-linked cold-chains. In this study, we used a perovskite catalyst prepared by the sol–gel method in synergy with a dual-component alcoholysis agent for the efficient degradation of waste PIR foam. The results suggest that the perovskite catalyst with LaNiO₃ was applied to degrade PIR for obtaining the lowest viscosity of the alcoholic digest (3768.4 mPa·s). Infrared spectral analysis indicated that the structure of the alcohol digest obtained after alcoholysis was similar to that of polyether polyol used in the production of PIR raw materials. The recycled PIR foam was obtained by partially replacing virgin polyol with an alcohol-decomposed material for refoaming, and had better thermal properties, higher apparent density, and compression strength than the virgin PIR foam. The results of this study can be an effective aid for the large-scale recycling and reuse of waste PIR foam.

引用次数: 0

New modification strategy for thermoplastic polyurethane with high hygrothermal ageing resistance and flame retardancy 具有高耐热老化性和阻燃性的热塑性聚氨酯改性新策略

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111140

Lvxing Wang , Saifei Xiang , Guangpu Ling , Jianbo Ying , Jiahui Zhou , Jintao Yang

Thermoplastic polyurethane (TPU) has been extensively used in many industrial communities, such as aerospace, electronics, and automotive manufacturing due to its remarkable mechanical strength, elasticity, and excellent chemical resistance. However, flammability and performance deterioration under high-temperature and high-humidity of TPU greatly limit its wider application. Herein, TPU composites with high hygrothermal ageing resistance and flame retardancy are prepared by introducing a molecularly engineered fluorinated thermoplastic polyurethane (FTPU) and synergistic flame retardant. The results show that the presence of FTPU greatly enhances the hydrophobicity of the matrix, impeding the diffusion of the water molecules into the composite, and alleviating the decrease of glass transition temperature and the rise of loss factor resulted from water plasticization effect. As a result, the TPU/FTPU composite shows a much higher mechanical property retention rate after immersing in water of 80 °C for 7 days, as compared to the pristine TPU. In addition, FTPU also exhibits synergistic effect with aluminum diethylphosphinate (ADP) and melamine cyanurate (MCA). The composite containing FTPU, ADP, and MCA (8 %, 4.5 %, and 4.5 %, respectively) can meet UL94 V-0 flame-retardant standard while the counterpart without FTPU shows UL94 V-2 flame retardancy. At the same time, such composite still exhibits tensile strength retention rate of 84.3 % after hygrothermal ageing treatment. This work provides a new modification strategy to simultaneously improve the hygrothermal ageing resistance and flame retardancy of TPU, which also can hopefully inspire the design of other polymers for high performance purpose.

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引用次数: 0

Measurement of monomers and oligomers (≤20mer) as intermediates using LC–Orbitrap MS from marine biodegradation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) in laboratory

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111166

Makoto Yasojima , Kana Kuroishi-Kawabe , Chihiro Nouda-Ibushi , Ryo Fujita , Takaki Mine , Hiroaki Takemori , Masao Kunioka

Degraded intermediates in the marine biodegradation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), a microbial polyester, were detected and quantified using LCOrbitrap MS. Intermediates were extracted from a biofilm (BF) attached to the biodegraded film using solvent extraction. Monomers and oligomers up to 11mer were identified on the surface of a marine biodegraded PHBH film and in the associated BF. The biodegradability and intermediate amounts of three films (ca. 90 mg) on day 9 were 13 % and 9.2 μg in the first test, 30 % and 13 μg in the second test, and 52 % and 19 μg in the third test, respectively. Differences in biodegradability and intermediate amounts between the biodegradation tests suggest that variation in the microbial community and quantity in seawater affect enzymatic degradation and mineralization rates. The amounts of 3-hydroxybutyric acid (3HB) monomer, 3-hydroxyhexanoate (3HH) monomer, and oligomers (3HB equivalent) were 67:5:28 (9.2 μg) in the first test, 69:5:26 (13 μg) in the second test, and 79:7:14 (19 μg) in the third test, respectively. The substantial occupancy of monomers in the intermediates suggests that the oligomers are rapidly enzymatically degraded into monomers, which are slowly mineralized and metabolized. Monomers were the only species identified in the pore water (free water within the BF), and the concentrations of intermediates in seawater were below the detection limit. The monomer composition (3HB:3HH) in the intermediate was consistent with the copolymer composition, indicating no selective accumulation of specific monomers.

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引用次数: 0

Analysis of high-molecular weight polyethylene glycol degradation by Pseudomonas sp.

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-01 DOI: 10.1016/j.polymdegradstab.2024.111144

M. Geisler , J. Khan , T. Heine , M.B. Ansorge-Schumacher , J. Thiele , A. Kaufmann

Polyethylene glycol (PEG) has widespread applications in pharmacy, medicine, and cosmetics, but its biological degradation is not completely understood, especially because of the complex analytics required for determining changes in molar mass and side or end groups, respectively. Here, we describe the activity of Pseudomonas sp. on PEG with molar masses of 6,000, 20,000 and 40,000 g mol⁻¹. The molar mass distribution after degradation was analyzed by size-exclusion chromatography (SEC) with different detection methods as well as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the differences between the results demonstrated. Further, the influence of the complex bacterial cultivation medium on analysis results was discussed. MALDI-TOF MS analysis revealed hydroxyethylene end-units on the PEG-terminus after bacterial degradation providing hints on the bacterial degradation pathway via end-unit scissioning followed by oxidation of the cleaved unit.

引用次数: 0

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