This article presents the different flame retardant (FR) additives adapted to polypropylene (PP) and their mode of actions when incorporated into the bulk. PP is naturally highly flammable; this review highlights the challenges to improve its flame retardant properties. It first reports the thermal degradation of PP and then focuses on FR PP systems and shows the high flame retardancy effectiveness of intumescent flame retardant (IFR) systems providing an efficient protective layer. It also highlights the need to improve the IFR systems to reduce the amount of FRs, using synergists, bio-based compounds or modified additives, but also using other effective systems such as free radical generators systems in combination with phosphorous flame retardant agent. Therefore, this article explores the effectiveness of several FR systems and highlight their mechanism of action in PP.
{"title":"Flame-retardants for polypropylene: A review","authors":"Séverine Bellayer , Melvin Dilger , Sophie Duquesne , Maude Jimenez","doi":"10.1016/j.polymdegradstab.2024.111008","DOIUrl":"10.1016/j.polymdegradstab.2024.111008","url":null,"abstract":"<div><p>This article presents the different flame retardant (FR) additives adapted to polypropylene (PP) and their mode of actions when incorporated into the bulk. PP is naturally highly flammable; this review highlights the challenges to improve its flame retardant properties. It first reports the thermal degradation of PP and then focuses on FR PP systems and shows the high flame retardancy effectiveness of intumescent flame retardant (IFR) systems providing an efficient protective layer. It also highlights the need to improve the IFR systems to reduce the amount of FRs, using synergists, bio-based compounds or modified additives, but also using other effective systems such as free radical generators systems in combination with phosphorous flame retardant agent. Therefore, this article explores the effectiveness of several FR systems and highlight their mechanism of action in PP.</p></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111008"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.polymdegradstab.2024.111011
Yuya Fukata, Satoshi Kimura, Tadahisa Iwata
Printed circuit boards (PCBs) contain metals and plastics, with the latter often incinerated after disposal, leading to carbon dioxide emissions. This study focuses on developing biomass-based thermosetting resins derived from polysaccharides. Cellulose and α-1,3-glucan were introduced with unsaturated (2-butenoate) and saturated (hexanoate) ester groups to achieve appropriate properties for PCB applications. The synthesized polysaccharide esters, cellulose-2-butenoate-hexanoate and α-1,3-glucan-2-butenoate-hexanoate, demonstrated thermoformability at 150 °C, suitable for being laminated on circuit lines. After heating at 220 °C for 1 hour, the unsaturated parts of the polymers crosslinked, increasing the glass transition temperature to over 230 °C, making them potentially durable for the soldering process. The dielectric constant and dissipation factor of the crosslinked resins ranged from 2.5 to 2.7 and 0.012 to 0.014, respectively, outperforming conventional epoxy resins to reduce transmission loss. Additionally, the crosslinked films exhibited robust mechanical properties with tensile strengths exceeding 50 MPa. These results indicate that polysaccharide unsaturated esters are promising for use as PCB insulating resins, providing a sustainable alternative to petroleum-based materials.
{"title":"Low-dielectric thermosetting resins derived from polysaccharide unsaturated esters","authors":"Yuya Fukata, Satoshi Kimura, Tadahisa Iwata","doi":"10.1016/j.polymdegradstab.2024.111011","DOIUrl":"10.1016/j.polymdegradstab.2024.111011","url":null,"abstract":"<div><div>Printed circuit boards (PCBs) contain metals and plastics, with the latter often incinerated after disposal, leading to carbon dioxide emissions. This study focuses on developing biomass-based thermosetting resins derived from polysaccharides. Cellulose and α-1,3-glucan were introduced with unsaturated (2-butenoate) and saturated (hexanoate) ester groups to achieve appropriate properties for PCB applications. The synthesized polysaccharide esters, cellulose-2-butenoate-hexanoate and α-1,3-glucan-2-butenoate-hexanoate, demonstrated thermoformability at 150 °C, suitable for being laminated on circuit lines. After heating at 220 °C for 1 hour, the unsaturated parts of the polymers crosslinked, increasing the glass transition temperature to over 230 °C, making them potentially durable for the soldering process. The dielectric constant and dissipation factor of the crosslinked resins ranged from 2.5 to 2.7 and 0.012 to 0.014, respectively, outperforming conventional epoxy resins to reduce transmission loss. Additionally, the crosslinked films exhibited robust mechanical properties with tensile strengths exceeding 50 MPa. These results indicate that polysaccharide unsaturated esters are promising for use as PCB insulating resins, providing a sustainable alternative to petroleum-based materials.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111011"},"PeriodicalIF":6.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.polymdegradstab.2024.111014
Dávid Zoltán Pirityi , Tamás Bárány , Kornél Pölöskei
Thermomechanical devulcanization is a possible solution for the circular economy of EPDM rubber, as it removes covalent crosslinks from vulcanizates, resulting in a material similar to uncured rubber mixes. In this paper, sulfur-cured EPDM rubber was treated with thermomechanical stimuli: a) processing on a two-roll mill and in an internal mixer, and b) twin-screw extrusion. Horikx's analysis indicated a 75 % decrease in crosslink density with little polymer chain degradation. The resulting devulcanizates and non-devulcanized rubber crumb were added to the original rubber mix, yielding samples with 0, 25, 50, 75 and 100 wt% recycled rubber contents. Revulcanizates with up to 50 wt% devulcanizate content retained the tensile strength of the original rubber with a slight increase in modulus. Ultimately, batch devulcanization had the most promising results, and extrusion devulcanization was also more beneficial than using non-devulcanized rubber crumb. Crosslink density and morphological tests also support these findings.
{"title":"Recycling of EPDM rubber via thermomechanical devulcanization: Batch and continuous operations","authors":"Dávid Zoltán Pirityi , Tamás Bárány , Kornél Pölöskei","doi":"10.1016/j.polymdegradstab.2024.111014","DOIUrl":"10.1016/j.polymdegradstab.2024.111014","url":null,"abstract":"<div><div>Thermomechanical devulcanization is a possible solution for the circular economy of EPDM rubber, as it removes covalent crosslinks from vulcanizates, resulting in a material similar to uncured rubber mixes. In this paper, sulfur-cured EPDM rubber was treated with thermomechanical stimuli: a) processing on a two-roll mill and in an internal mixer, and b) twin-screw extrusion. Horikx's analysis indicated a 75 % decrease in crosslink density with little polymer chain degradation. The resulting devulcanizates and non-devulcanized rubber crumb were added to the original rubber mix, yielding samples with 0, 25, 50, 75 and 100 wt% recycled rubber contents. Revulcanizates with up to 50 wt% devulcanizate content retained the tensile strength of the original rubber with a slight increase in modulus. Ultimately, batch devulcanization had the most promising results, and extrusion devulcanization was also more beneficial than using non-devulcanized rubber crumb. Crosslink density and morphological tests also support these findings.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111014"},"PeriodicalIF":6.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.polymdegradstab.2024.111015
Jinyan Li, Yang Yu, Xiaolin Zhang
The design and development of biobased plastics that can degrade in seawater is a potential approach to address the seawater pollution of fossil plastics. Herein, N,N'-pentamethylene-bis(pyrrolidone-4-methyl carboxylate) (PBPC), a biobased diester with two pyrrolidone rings, was synthesized from renewable 1,5-pentanediamine and dimethyl itaconate. PBPC was polymerized with three α,ω-diols to prepare biobased homopolyesters with number-average molecular weight (Mn) around 25 kDa. These amorphous homopolyesters presented remarkable UV shielding abilities compared with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS). Incubation experiments in artificial seawater for 150 days indicated that the homopolyesters based on PBPC exhibited rapid seawater-degradability. Then, PBPC was copolymerized with 1,4-butanediol and terephthalic acid to prepare a series of copolyesters with Mn around 20 kDa. The introduction of PBPC into poly(butylene terephthalate) (PBT) resulted in the elevated toughness and sensitivity to seawater degradation. Depending on the composition of PBPC, the thermal, mechanical, and degradation rate of the copolyesters were adjustable. Overall, the PBPC-based polyesters are promising alternatives to commercial packaging materials in improving the renewability of raw materials and achieving seawater degradation.
{"title":"Synthesis of renewable and seawater-degradable polyesters based on a fully biobased diester","authors":"Jinyan Li, Yang Yu, Xiaolin Zhang","doi":"10.1016/j.polymdegradstab.2024.111015","DOIUrl":"10.1016/j.polymdegradstab.2024.111015","url":null,"abstract":"<div><div>The design and development of biobased plastics that can degrade in seawater is a potential approach to address the seawater pollution of fossil plastics. Herein, <em>N,N</em>'-pentamethylene-bis(pyrrolidone-4-methyl carboxylate) (PBPC), a biobased diester with two pyrrolidone rings, was synthesized from renewable 1,5-pentanediamine and dimethyl itaconate. PBPC was polymerized with three α,ω-diols to prepare biobased homopolyesters with number-average molecular weight (<em>M</em><sub>n</sub>) around 25 kDa. These amorphous homopolyesters presented remarkable UV shielding abilities compared with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS). Incubation experiments in artificial seawater for 150 days indicated that the homopolyesters based on PBPC exhibited rapid seawater-degradability. Then, PBPC was copolymerized with 1,4-butanediol and terephthalic acid to prepare a series of copolyesters with <em>M</em><sub>n</sub> around 20 kDa. The introduction of PBPC into poly(butylene terephthalate) (PBT) resulted in the elevated toughness and sensitivity to seawater degradation. Depending on the composition of PBPC, the thermal, mechanical, and degradation rate of the copolyesters were adjustable. Overall, the PBPC-based polyesters are promising alternatives to commercial packaging materials in improving the renewability of raw materials and achieving seawater degradation.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111015"},"PeriodicalIF":6.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.polymdegradstab.2024.111012
Xiaodi Ye , Cheng Zhan , Bingtao Wang , Ting Sai , Chengfeng Zhang , Juan Li , Zhenghong Guo , Siqi Huo
To cope with the practical demands of high-performance polycarbonate (PC) and explore the application of carbon black (CB) in flame retardant field, a sulfonated carbon black (CB-SS) was synthesized and applied to flame retardant PC in this work. Compared with PC/CB composite, PC/CB-SS composite displays better overall performances under the same flame retardant addition. The PC/3CB-SS composite with 3 wt.% of CB-SS achieves a vertical burning test (UL-94) V-0 rating with a limiting oxygen index (LOI) of 29.5%, and its peak heat release rate (PHRR) and total smoke release rate (TSR) are respectively reduced by 17% and 6% relative to those of PC/3CB with 3 wt.% of CB. The flame retardancy mechanism is proposed by analyzing the char residue obtained from cone calorimetry test, which confirms the synergistic flame-retardant effect between sodium sulfonate and CB in condensed phase. Moreover, PC/3CB-SS shows much better mechanical properties than PC/3CB, and its elongation at break is increased by 223% compared with that of PC/3CB. This is mainly due to the more even dispersion of CB-SS within PC and the stronger interfacial force between CB-SS and PC. This work provides an effective approach for the creation of fire-retardant and smoke-suppressive PC composites with well-preserved mechanical properties, contributing to expanding the industrial applications of PC.
{"title":"Engineering sulfonated carbon black for flame-retardant and smoke-suppressive polycarbonate with well-preserved mechanical performances","authors":"Xiaodi Ye , Cheng Zhan , Bingtao Wang , Ting Sai , Chengfeng Zhang , Juan Li , Zhenghong Guo , Siqi Huo","doi":"10.1016/j.polymdegradstab.2024.111012","DOIUrl":"10.1016/j.polymdegradstab.2024.111012","url":null,"abstract":"<div><div>To cope with the practical demands of high-performance polycarbonate (PC) and explore the application of carbon black (CB) in flame retardant field, a sulfonated carbon black (CB-SS) was synthesized and applied to flame retardant PC in this work. Compared with PC/CB composite, PC/CB-SS composite displays better overall performances under the same flame retardant addition. The PC/3CB-SS composite with 3 wt.% of CB-SS achieves a vertical burning test (UL-94) V-0 rating with a limiting oxygen index (LOI) of 29.5%, and its peak heat release rate (PHRR) and total smoke release rate (TSR) are respectively reduced by 17% and 6% relative to those of PC/3CB with 3 wt.% of CB. The flame retardancy mechanism is proposed by analyzing the char residue obtained from cone calorimetry test, which confirms the synergistic flame-retardant effect between sodium sulfonate and CB in condensed phase. Moreover, PC/3CB-SS shows much better mechanical properties than PC/3CB, and its elongation at break is increased by 223% compared with that of PC/3CB. This is mainly due to the more even dispersion of CB-SS within PC and the stronger interfacial force between CB-SS and PC. This work provides an effective approach for the creation of fire-retardant and smoke-suppressive PC composites with well-preserved mechanical properties, contributing to expanding the industrial applications of PC.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111012"},"PeriodicalIF":6.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.polymdegradstab.2024.111013
Xiao-Hui Shi , Huan Luo , Cheng-Yue Jing , Hong Shi , De-Yi Wang
Inspired by the significant synergistic effect of transition metals and ammonium polyphosphate (APP) on flame reatrdancy, a nickel/cobalt-layered double hydroxide derived from a selected zeolitic imidazolate framework-67 (APP@NiCo) was constructed onto the surface of APP to enhance the fire safety of thermoplastic polyurethane (TPU). The results demonstrated that TPU containing 6 wt% APP@NiCo exhibited a LOI value of 27.7 % and achieved UL-94 V-0 rating. Furthermore, there was a significant reduction in the peak heat release rate, heat release rate, and total smoke production by 72.8 %, 37.5 % and 56.9 %, respectively. The remarkable improvement in flame retardancy was contributed to the highly synergistic charring catalysis of APP and dual transition metals cobalt and nickel, which effectively promoted the formation of robust char layers during TPU combustion for enhancing fire safety.
{"title":"The preparation of ammonium polyphosphate@ nickel/cobalt-layered double hydroxide and its application as flame retardant in thermoplastic polyurethane","authors":"Xiao-Hui Shi , Huan Luo , Cheng-Yue Jing , Hong Shi , De-Yi Wang","doi":"10.1016/j.polymdegradstab.2024.111013","DOIUrl":"10.1016/j.polymdegradstab.2024.111013","url":null,"abstract":"<div><div>Inspired by the significant synergistic effect of transition metals and ammonium polyphosphate (APP) on flame reatrdancy, a nickel/cobalt-layered double hydroxide derived from a selected zeolitic imidazolate framework-67 (APP@NiCo) was constructed onto the surface of APP to enhance the fire safety of thermoplastic polyurethane (TPU). The results demonstrated that TPU containing 6 wt% APP@NiCo exhibited a LOI value of 27.7 % and achieved UL-94 V-0 rating. Furthermore, there was a significant reduction in the peak heat release rate, heat release rate, and total smoke production by 72.8 %, 37.5 % and 56.9 %, respectively. The remarkable improvement in flame retardancy was contributed to the highly synergistic charring catalysis of APP and dual transition metals cobalt and nickel, which effectively promoted the formation of robust char layers during TPU combustion for enhancing fire safety.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111013"},"PeriodicalIF":6.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.polymdegradstab.2024.111010
Zhaoshun Zhan , Shihan Weng , Tianyou Bao , Lina Yan , Fanna Meng , Lixin Li
Currently, it is still a challenge to endow polylactic acid (PLA) with excellent degradation and fire safety. In this work, we have extracted a novel phosvitin aiming to achieve the fire resistance and degradation of PLA. Employing the phosvitin, the PLA composite exhibits conspicuous fire resistance with an LOI of 27.4 % and a V-0 rating in the UL-94 tests by controlling the added volume at 40 wt.%. Simultaneously, the thermal stability and fire behaviour of the PLA composite have been improved by the plentiful char residue formation. The flame-retardant mechanism of phosvitin in PLA material has been deduced by TG-IR, FTIR XPS and SEM. The phosvitin containing abundant P-O, P = O and P-N functional groups generates phosphorus-containing compounds to promote the dehydration reaction of the PLA matrix in a condensed phase. This is beneficial to improve the flame retardancy of PLA by the formation of a char layer, providing the shielding effect to prevent the heat transfer and flammable micro-molecules volatilisation process. Likewise, the affluent phosphorus-containing compounds included in the phosvitin possess fabulous catalytic action to destroy the PLA into small molecular weight fragment which shows a beneficial to promote the degradation reaction of PLA composite. Hence, the phosvitin is important to expand the range of applications of PLA materials to develop sustainable multifunctional materials.
{"title":"Simultaneously boosting the flame retardancy and degradability of poly(lactic acid) composite by phosvitin affiliation","authors":"Zhaoshun Zhan , Shihan Weng , Tianyou Bao , Lina Yan , Fanna Meng , Lixin Li","doi":"10.1016/j.polymdegradstab.2024.111010","DOIUrl":"10.1016/j.polymdegradstab.2024.111010","url":null,"abstract":"<div><div>Currently, it is still a challenge to endow polylactic acid (PLA) with excellent degradation and fire safety. In this work, we have extracted a novel phosvitin aiming to achieve the fire resistance and degradation of PLA. Employing the phosvitin, the PLA composite exhibits conspicuous fire resistance with an LOI of 27.4 % and a V-0 rating in the UL-94 tests by controlling the added volume at 40 wt.%. Simultaneously, the thermal stability and fire behaviour of the PLA composite have been improved by the plentiful char residue formation. The flame-retardant mechanism of phosvitin in PLA material has been deduced by TG-IR, FTIR XPS and SEM. The phosvitin containing abundant P-O, <em>P</em> = <em>O</em> and P-N functional groups generates phosphorus-containing compounds to promote the dehydration reaction of the PLA matrix in a condensed phase. This is beneficial to improve the flame retardancy of PLA by the formation of a char layer, providing the shielding effect to prevent the heat transfer and flammable micro-molecules volatilisation process. Likewise, the affluent phosphorus-containing compounds included in the phosvitin possess fabulous catalytic action to destroy the PLA into small molecular weight fragment which shows a beneficial to promote the degradation reaction of PLA composite. Hence, the phosvitin is important to expand the range of applications of PLA materials to develop sustainable multifunctional materials.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111010"},"PeriodicalIF":6.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.polymdegradstab.2024.111009
Tengfei Han , Yanshai Wang , Shufen Zhang , Benzhi Ju
Cellulose is the most abundant natural polypolysaccharide and is an ideal raw material to replace petroleum-based plastics. However, natural cellulose is difficult to be thermo-processed like conventional plastics because of the rich and strong hydrogen bonds interactions. In this study, a series of dialdehyde derivatives of cellulose (DACs) were prepared by periodate oxidation of cellulose, and cellulose covalent adaptive networks based on acetal dynamic covalent bonds (ACCs) were prepared using dipentaerythritol as a crosslinker for DAC. This strategy can introduce acetal bonds, weaken hydrogen bonds, and reduce rigidity to kill three birds with one stone. The excellent reprocessing performance of ACCs is attributed to the reconstruction of the cellulose hydrogen bond network by acetal bonds, and the reversible exchange reaction of the acetal bonds at high temperatures endows the cellulose chains with mobility, allowing ACCs to be remodeled by hot pressing at 90°C for 15 min. The excellent stability and reprocessability of ACCs hold the promise of replacing current non-renewable petroleum-based plastics and provide inspiration for the development of other types of biomass plastics.
{"title":"“Three birds with one stone” strategy for building easily reprocessable cellulosic thermosetting resins","authors":"Tengfei Han , Yanshai Wang , Shufen Zhang , Benzhi Ju","doi":"10.1016/j.polymdegradstab.2024.111009","DOIUrl":"10.1016/j.polymdegradstab.2024.111009","url":null,"abstract":"<div><div>Cellulose is the most abundant natural polypolysaccharide and is an ideal raw material to replace petroleum-based plastics. However, natural cellulose is difficult to be thermo-processed like conventional plastics because of the rich and strong hydrogen bonds interactions. In this study, a series of dialdehyde derivatives of cellulose (DACs) were prepared by periodate oxidation of cellulose, and cellulose covalent adaptive networks based on acetal dynamic covalent bonds (ACCs) were prepared using dipentaerythritol as a crosslinker for DAC. This strategy can introduce acetal bonds, weaken hydrogen bonds, and reduce rigidity to kill three birds with one stone. The excellent reprocessing performance of ACCs is attributed to the reconstruction of the cellulose hydrogen bond network by acetal bonds, and the reversible exchange reaction of the acetal bonds at high temperatures endows the cellulose chains with mobility, allowing ACCs to be remodeled by hot pressing at 90°C for 15 min. The excellent stability and reprocessability of ACCs hold the promise of replacing current non-renewable petroleum-based plastics and provide inspiration for the development of other types of biomass plastics.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111009"},"PeriodicalIF":6.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.1016/j.polymdegradstab.2024.111007
Takuma Kobayashi , Toshiaki Nakajima-Kambe
Poly(glycolic acid) (PGA) is widely utilized in the shale oil and gas industry owing to its biodegradable nature, as well as superior mechanical and barrier properties. However, PGA degradability is limited by environmental conditions such as temperature and pH, and using acids to optimize the degradation can have adverse environmental impact. Thus, it is essential to identify methods that can effectively promote the degradation of PGA under mild conditions, such as microbial degradation. In the present study, strain DB14, a bacterium that promotes PGA degradation, was isolated from drain water of a steam pipeline. Sequence analysis of the 16S rRNA gene of the bacterium revealed that it is mostly closely related to Geobacillus icigianus; however, it also differed from Geobacillus icigianus in several physiological properties. To investigate PGA degradation by strain DB14, a PGA film and disc were incubated with the strain. The residual weight of the PGA film (thickness: 170 μm) significantly reduced after incubation, whereas the decrease in the thickness of the PGA disc (thickness: 3 mm) was relatively small. The penetration of water, the bacterium, and the extracellular enzymes into the interior from the reaction-erosion front of the PGA disc may be inhibited by the high barrier performance of PGA. Strain DB14 was also found to change the pH of the surrounding environment to approximately 8–9. To investigate the effect of pH on PGA degradability, degradation tests with crude extracellular enzymes derived from strain DB14 were conducted in various buffers. The results showed that the degradation activity was highest at pH 8, which implied that DB14 efficiently maximized the hydrolytic capacity of its enzyme for degrading PGA. Thus, this study provides a basis for developing environmentally friendly technologies that can promote the degradation of PGA molding articles, especially those used in wellbores for oil and gas recovery.
{"title":"Isolation and characterization of a novel bacterium that promotes the degradation of poly(glycolic acid) by its extracellular esterase under thermophilic conditions","authors":"Takuma Kobayashi , Toshiaki Nakajima-Kambe","doi":"10.1016/j.polymdegradstab.2024.111007","DOIUrl":"10.1016/j.polymdegradstab.2024.111007","url":null,"abstract":"<div><p>Poly(glycolic acid) (PGA) is widely utilized in the shale oil and gas industry owing to its biodegradable nature, as well as superior mechanical and barrier properties. However, PGA degradability is limited by environmental conditions such as temperature and pH, and using acids to optimize the degradation can have adverse environmental impact. Thus, it is essential to identify methods that can effectively promote the degradation of PGA under mild conditions, such as microbial degradation. In the present study, strain DB14, a bacterium that promotes PGA degradation, was isolated from drain water of a steam pipeline. Sequence analysis of the 16S rRNA gene of the bacterium revealed that it is mostly closely related to <em>Geobacillus icigianus</em>; however, it also differed from <em>Geobacillus icigianus</em> in several physiological properties. To investigate PGA degradation by strain DB14, a PGA film and disc were incubated with the strain. The residual weight of the PGA film (thickness: 170 μm) significantly reduced after incubation, whereas the decrease in the thickness of the PGA disc (thickness: 3 mm) was relatively small. The penetration of water, the bacterium, and the extracellular enzymes into the interior from the reaction-erosion front of the PGA disc may be inhibited by the high barrier performance of PGA. Strain DB14 was also found to change the pH of the surrounding environment to approximately 8–9. To investigate the effect of pH on PGA degradability, degradation tests with crude extracellular enzymes derived from strain DB14 were conducted in various buffers. The results showed that the degradation activity was highest at pH 8, which implied that DB14 efficiently maximized the hydrolytic capacity of its enzyme for degrading PGA. Thus, this study provides a basis for developing environmentally friendly technologies that can promote the degradation of PGA molding articles, especially those used in wellbores for oil and gas recovery.</p></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111007"},"PeriodicalIF":6.3,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-14DOI: 10.1016/j.polymdegradstab.2024.110981
Ran Wang, Teng Fu, Ya-Jie Yang, Xiu-Li Wang, Yu-Zhong Wang
Fire-safety polymer materials are essential in modern society such as electronics, aerospace, new energy. The quantification and prediction of flame retardancy, determined by the chemical composition and the burning process, has always been a bottleneck challenge. Previous empirical design rules and the existing models show large deviations for predicting flame retardancy and are often unexplainable. Here, this study proposes an interpretable model that can quantify the groups contribution of flame-retardancy and predict the flame retardance of intrinsically flame-retardant polymers. The machine learning model simultaneously considers the group structures and their flame-retardant mechanism in both the gas phase and condensed phase, achieving high prediction accuracy (89.8% for the training set and 83.8% for the testing set). It also quantifies the contribution values of various flame-retardant groups (halogen-containing structures, phosphorus-containing structures, phosphorus-nitrogen-containing structures, aromatic ring-containing structures, etc.) in both phases for the first time. The running script that integrates the model has also been open-sourced, providing an emerging strategy for transitioning flame-retardant research from empirical methods to scientific design.
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