Linear low⁃density polyethylene cast films with thicknesses ranging from 9 to 135 μm were prepared by varying the feed screw speed. The crystalline structure and surface morphology of these films were characterized using differential scanning calorimetry （DSC）， wide⁃angle X⁃ray diffraction， small⁃angle X⁃ray scattering， light scattering， and white light interferometry. The influence of thickness reduction on haze and mechanical properties was systematically investigated. The results show that when the film thickness decreases below 33 μm， significant structural changes occur across multiple length scales， including the unit cell， lamellae， and spherulites. In particular， at a thickness of 9 μm， the （110） crystal plane diffraction peak exhibits pronounced splitting， and the Hermans orientation factor of the lamellae increases. No spherulites are observed in the thinnest films， and the shoulder peak in the DSC melting curve becomes more distinct. As thickness decreases， haze initially declines and then rises. Tensile strength in the machine direction remains relatively stable， whereas that in the transverse direction decreases. Elongation at break shows little change initially and then decreases with further thinning. Tear strength in the machine direction first decreases and then increases， while puncture strength exhibits an overall increasing trend.

Silane⁃modified carbon nitride （CN⁃KH560） was prepared by coating carbon nitride nanosheets （CNNS） with a hydrophilic layer formed from γ⁃glycidyloxypropyltrimethoxysilane （KH560） and polydopamine. This modified filler was incorporated into epoxy resin （EP） in combination with ammonium polyphosphate （APP） at optimized ratios to fabricate flame⁃retardant EP composites. The resulting materials were evaluated for their flame retardancy， smoke suppression， and mechanical properties. The results show that when 9 wt% APP and 1 wt% CN⁃KH560 were added， the EP/9APP/1CN⁃KH560 composite achieved a UL 94 V⁃0 rating in the vertical burning test and exhibited a limiting oxygen index of 40.2 %. Compared with neat EP， the composite reduced total heat release and total smoke production by 48.76 % and 53.5 %， respectively. Moreover， the EP/9APP/1CN⁃KH560 composite retained the excellent mechanical properties of the base epoxy resin.

Vanillin⁃based monomer of benzene dicarbonitrile was synthesized using biomass vanillin as raw material， and compounded with different contents of polyhedral oligomeric silsesquioxane （POSS） to prepare POSS/vanillin⁃based benzene dicarbonitrile resin composites. The experimental results showed that the initial thermal decomposition temperature of the resin with 10 wt% POSS added was significantly increased by more than 140 ℃， enhancing the thermal stability of the resin. The introduction of 1 wt% POSS can improve the mechanical properties of the resin， thereby enhancing the mechanical properties of the polymer. With the increase of POSS content， the water absorption rate of the resin showed a gradual decreasing trend， resulting in reduced water absorption performance.

This study employed a dry⁃swelling method to fabricate a polyvinyl alcohol （PVA）/poly（N⁃hydroxymethyl acrylamide） （PNHMA） interpenetrating network hydrogel， denoted as V⁃PNₓM50. Ammonium molybdate （Mo7） was subsequently incorporated into the hydrogel to yield a photochromic material exhibiting high mechanical strength and tunable light⁃responsive coloration. The photochromic properties， fading behavior， hydrochromic performance， and potential for information storage applications were systematically investigated. The results indicate that the hydrogel achieved a tensile strength of up to 18 MPa and displayed temperature⁃dependent photochromism. Lowering the temperature shifts the light⁃induced color from blue⁃green to yellow⁃green or yellow. Following photochromic activation， the V⁃PNₓM50 hydrogel exhibits a “three⁃stage” sequential hydrochromic process： “fast fading → slow color change → prolonged fading.” By adjusting the NHMA content， both the duration and color intensity of each hydrochromic stage could be controlled， with underwater color retention lasting up to 18 days. Moreover， the hydrogel enables high⁃resolution “photo⁃printing”， demonstrating promising potential as a material for optical information storage.

This study investigates the effects of toner type， toughening agents， and lubricants on the mechanical properties and surface aesthetics， specifically gloss and blackness， of polymethyl methacrylate （PMMA）. The influence mechanism of toughening agents on blackness is also analyzed. The results indicate that PMMA formulated with a self⁃developed organic black pigment exhibits superior blackness and gloss compared to carbon black⁃based formulations， achieving a more pronounced piano black effect. Among the tested toughening agents， the transparent agent （M⁃270） significantly enhances the material’s toughness while preserving its high⁃gloss， deep⁃black appearance. At a PMMA/M⁃270 mass ratio of 90/10， the impact toughness increases by nearly 40 % relative to neat PMMA. Lubricants were found to moderately affect mechanical performance， with ethylene bis⁃stearamide demonstrating the best overall balance of properties.

Poly（butylene adipate⁃co⁃terephthalate） （PBAT）， polylactic acid （PLA）， CaCO₃， and various adsorbents were melt⁃blended to investigate how different adsorbent types affect the mechanical performance and emission behavior of the resulting composites. The results show that adsorbents with larger particle sizes， specifically INFLIM300 and MS10E， significantly degraded film properties， whereas M50， which features finer particles， caused only a modest decline in mechanical performance. Both magnesium silicate⁃based adsorbents （MS10E and M50） exhibit excellent odor⁃removal efficiency： adding 3 wt% of either reduced film odor by 24.2 % and 25.4 %， respectively. However， increasing the M50 loading to 4 wt% leads to a slight rebound in odor intensity. Notably， the incorporation of more than 3 wt% adsorbents results in higher total volatile organic compound （VOC） emissions compared to the blank sample. Detailed VOC analysis reveals reductions in five benzene derivatives and three aldehydes， yet the overall concentration of C6–C16 hydrocarbons increased to varying extents. Fogging tests further show decreased gloss retention on glass slides and denser oil stains upon adsorbent addition. This phenomenon is attributed to excessive adsorbent content intensifying shear forces and thermal stress during melt processing， which promotes polymer chain scission and generates more low⁃ to medium⁃molecular⁃weight species. While the adsorbents effectively capture small volatile molecules， their capacity to retain medium⁃sized compounds remains limited.

Ethylene⁃butyl acrylate copolymer （EBA） was employed as the matrix resin， and a highly conductive carbon black （CB） was used as the conductive filler to fabricate semi⁃conductive shielding materials via melt blending， with CB loadings varied from 18 wt% to 34 wt%. The results show that increasing CB content significantly reduces the volume resistivity， weakens the positive temperature coefficient （PTC） effect， and enhances the thermal stability of electrical properties. At a CB loading of 34 wt%， the shielding material presents a room⁃temperature volume resistivity of 11.4 Ω·cm along with a PTC of 11.7. The tensile strength exhibits a non⁃monotonic trend， initially increasing and then decreasing with higher CB content， while the elongation at break consistently declines. Dynamic mechanical analysis reveals that the percolated CB network strengthens interfacial interactions within the composite， thereby increasing both the storage modulus and loss modulus， while simultaneously restricting segmental mobility and chain slippage of the EBA matrix. Rheological measurements further confirm that all formulations display typical shear⁃thinning behavior， with the storage modulus， loss modulus， and complex viscosity progressively rising as CB content increases， indicative of a well⁃developed conductive filler network.

This study presents the design， fabrication， and characterization of segmented polymer microneedles for the transdermal delivery of sitagliptin. The microneedle geometry and array architecture were specifically engineered to enable efficient drug administration. Comprehensive evaluations of morphology， dimensional accuracy， and mechanical properties confirmed that the fabricated microneedles possess sufficient structural integrity to reliably penetrate the stratum corneum. In vitro transdermal diffusion tests demonstrated rapid and sustained drug release： 72.3 % of the loaded sitagliptin was released within 2 min， and cumulative release reached 97.1 % by 10 min. These results highlight the excellent drug release kinetics and potential clinical utility of the developed system. Given sitagliptin’s therapeutic relevance in metabolic disorders， this microneedle platform offers a promising， minimally invasive strategy for the management of obesity and related conditions.

Detecting weld defects in polyethylene pipelines remains challenging due to low defect visibility， complex background interference， and high variability in defect morphology as factors that traditionally necessitate extensive human expertise. To address these limitations， this study presents FWD⁃YOLO， an improved object detection model based on YOLOv8n， specifically tailored for weld defect inspection. Key enhancements include： （1） replacing the standard Conv and C2f modules in the backbone with more efficient alternatives； （2） integrating the dynamic sampling module DySample into the neck to improve robustness against geometric deformations and cluttered backgrounds； （3） introducing a multi⁃layer channel attention mechanism to facilitate effective multi⁃scale feature fusion； and （4） optimizing the loss function to better balance precision and recall. Evaluated on a self⁃constructed dataset encompassing nine distinct defect categories， FWD⁃YOLO achieves a 4.8 % absolute improvement in mAP@50 （reaching 73.3 %）， a 3 % gain in recall， while simultaneously reducing model parameters by 22.4 % and floating⁃point operations （FLOPs） by 42.6 % compared to the original YOLOv8n. Furthermore， FWD⁃YOLO outperforms other lightweight YOLO variants， including YOLOv5n， YOLOv6n， YOLOv9t， YOLOv10n， YOLOv11n， and YOLOv12n， in terms of detection accuracy. These results demonstrate that FWD⁃YOLO offers an efficient， accurate， and deployable solution for automated quality inspection of polyethylene pipeline welds， thereby contributing to the safe and reliable operation of pipeline infrastructure.

Building upon the BiLSTM–Attention neural network model， this study quantitatively selects relevant input parameters using the mutual information method， ranks the importance of process variables influencing melt pressure at the extruder outlet， and investigates the effects of input parameter dimensionality and time⁃series length on the model’s prediction accuracy and stability. The results indicate that the highest prediction accuracy and stability are achieved when the two parameters with the largest mutual information values， along with the melt pressure itself， are retained as input features. Furthermore， selecting an appropriate length for the input time⁃series sequence significantly influences the model’s predictive performance. Comparative experiments show that the BiLSTM⁃Attention model outperforms both the standard LSTM and BiLSTM models in terms of prediction accuracy and stability. These findings provide an effective data⁃driven theoretical approach for applications involving twin⁃screw extruders where stringent control of outlet melt pressure stability is required. Building upon the BiLSTM⁃Attention neural network model， this study quantitatively selects relevant input parameters using the mutual information method， ranks the importance of process variables influencing melt pressure at the extruder outlet， and investigates the effects of input parameter dimensionality and time⁃series length on the model’s prediction accuracy and stability. The results indicate that the highest prediction accuracy and stability are achieved when the two parameters with the largest mutual information values， along with the melt pressure itself， are retained as input features. Furthermore， selecting an appropriate length for the input time⁃series sequence significantly influences the model’s predictive performance. Comparative experiments show that the BiLSTM⁃Attention model outperforms both the standard LSTM and BiLSTM models in terms of prediction accuracy and stability.

Regarding the current issue of long construction time for ship hull thermal insulation materials， this study proposes accurate and reasonable improvement measures and solutions through multi⁃factor analysis and investigative verification， focusing on two aspects： standardized prefabricated profile blocks and an optimized curing agent ratio. Further experimental verification confirms that the proposed approach achieves the expected target requirements， delivers significant improvement effects， and substantially reduces the construction time of thermal insulation materials in ship hulls.

This study proposes a hybrid modeling approach that integrates principal component analysis （PCA） with the eXtreme Gradient Boosting （XGBoost） algorithm to address challenges such as multi⁃parameter coupling and strong nonlinear correlations in the injection molding process. Using process parameters collected from an actual production line， dimensionality inconsistencies among features were first eliminated via Z⁃score standardization. Subsequently， PCA was applied to reduce the dimensionality of the input variables， thereby compressing feature space and mitigating the adverse effects of redundant information on model performance. On this basis， a regression model was developed to predict the product qualification rate and compared with a baseline XGBoost model without dimensionality reduction. Results show that the PCA⁃XGBoost model achieves a determination coefficient （R²） of 0.981 7 on the test set， outperforming the undiminished model （R²=0.962 0）， with the mean absolute error reduced by approximately 45 %. Feature importance analysis reveals that several variables associated with the injection molding cycle carry high weights in the modeling process， and dimensionality reduction helps enhance the model’s ability to identify key influencing factors. The proposed model has been deployed on a food container injection molding production line and continuously validated across multiple batches. Under consistent conditions of equipment， raw materials， and process flow， the product qualification rate improved from 96.7 % to 99.82 %.

In this work， two polyhedral oligomeric silsesquioxane （POSS）⁃based crosslinkers， denoted as CD⁃POSS， each bearing both a 9，10⁃dihydro⁃9⁃oxa⁃10⁃phosphaphenanthrene⁃10⁃oxide （DOPO）⁃derived flame⁃retardant group and a siloxane crosslinking functionality， were synthesized via a one⁃step route. The chemical structures of CD⁃POSS were confirmed by NMR， FTIR， and mass spectrometry. CD⁃POSS was subsequently employed as a flame⁃retardant crosslinker in room⁃temperature vulcanized silicone rubber （SR⁃CDPOSS）. Among the variants， 6C2D⁃POSS exhibits excellent compatibility with silicone rubber， achieving uniform dispersion without agglomeration， and delivered superior flame retardancy and thermal stability. The resulting SR⁃6C2DPOSS attained a UL 94 V⁃0 rating in vertical burning tests， and its limiting oxygen index increased from 24.5 % to 29.8 %. Moreover， the peak heat release rate and peak smoke production rate are reduced to 223 kW/m² and 0.101 m²/s， respectively， representing decreases of 48.7 % and 48.8 % compared to silicone rubber crosslinked with ethyl orthosilicate. Thermogravimetric analysis indicates that SR⁃6C2DPOSS suppresses the decomposition of terminal hydroxyl groups and promotes char formation during combustion， suggesting that its flame⁃retardant action primarily occurs in the condensed phase.

A novel hyperbranched flame retardant featuring dual functionality， nitrogen⁃phosphorus synergistic flame retardancy and intrinsic toughening capability， was synthesized via a nucleophilic substitution reaction using difunctional phenyl dichlorophosphate and trifunctional triethanolamine as building blocks. This additive was incorporated into epoxy resin to simultaneously mitigate its inherent flammability and brittleness. The resulting composites were systematically characterized for thermal stability， flame retardancy， and mechanical performance. Thermogravimetric analysis reveals that the flame retardant significantly promoted char formation， thereby enhancing fire resistance. Notably， at a loading of 7.5 wt%， the epoxy composite achieved a UL 94 V⁃0 rating with a limiting oxygen index of 33.4 %. Moreover， the hyperbranched architecture of the additive imparts remarkable toughening effects. At just 5 wt% loading， the epoxy composite obtained increases in the tensile strength （103.1 MPa）， flexural strength （112.3 MPa）， impact strength （13.0 kJ/m²）， and elongation at break （8.5 %） by 48.9 %， 25.7 %， 27.4 %， and 46.1 %， respectively， compared to the neat epoxy resin. These results demonstrate that the designed flame retardant effectively balances flame inhibition and mechanical reinforcement in epoxy systems.

This study employs the life cycle assessment methodology to quantify and compare the carbon footprints of recycled and virgin form⁃fill⁃seal films， with a focus on identifying key sources of greenhouse gas emissions across their life cycles. The results indicate that raw material production is the dominant contributor to the overall carbon footprint. Substituting a portion of virgin polyethylene （PE） with recycled PE significantly reduces the product′s embodied carbon emissions. Furthermore， process optimization， such as integrated technological upgrades， and the adoption of renewable energy sources， particularly solar⁃generated electricity， offer additional， albeit more modest， emission reduction benefits.

In this study， a composite additive was prepared by physically blending sodium 2，2’⁃methylenebis（4，6⁃di⁃tert⁃butylphenyl） phosphate （NA⁃11） with oleamide （OAM）， and applied to modify recycled polypropylene （rPP）. The non⁃isothermal crystallization behavior， mechanical properties， anti⁃slip performance， and wear resistance of the blend system were systematically investigated. The results indicate that NA⁃11 significantly increases the crystallization temperature of rPP， shortens its half⁃crystallization time， and accelerates the crystallization rate. Meanwhile， the mechanical properties of the blend system exhibited a corresponding improvement. This enhancing effect became more pronounced when NA⁃11 was used in combination with OAM. Specifically， the rPP/NA⁃11O composite showed a crystallization temperature （T_c） of 128.79 ℃， an impact strength of 29.4 kJ/m²， and a flexural strength of 147.5 MPa. Furthermore， the anti⁃slip and wear resistance properties of rPP/NA⁃11O met the core requirements of the Hebei Provincial Local Standard 《Technical Specification for Suspended Assembly Sports Floor》 （DB 13/T 5088—2019）.

Taking into account the structural characteristics of the funnel⁃shaped plastic part， a three⁃plate injection mold featuring a stationary⁃mold core⁃pulling mechanism was developed. The cavity insert adopts a Half structure， which achieves two⁃step mold separation through the coordinated action of compression springs. The slider performs inclined core pulling driven by the mold⁃opening force， and the entire core⁃pulling mechanism is integrated within the mold body. This integration improves molding accuracy and simplifies the overall mold structure. Loop⁃type and well⁃type cooling circuits are arranged on the split cavity and core， respectively， ensuring uniform cooling to prevent injection defects and reduce cycle time. Attention was also paid to molding and processing technology in the detailed design： balance blocks and support columns were incorporated to mitigate defects caused by imbalanced injection pressure. Additionally， anti⁃rotation structures for both the core and ejector pins were implemented to enhance positioning accuracy. Overall， the proposed mold design simplifies the structure， improves injection precision， and demonstrates practical value in production applications.

This paper reviews the research progress on the degradation of poly（glycolic acid） （PGA）. It provides a detailed introduction to the factors influencing PGA degradation and its underlying mechanisms， summarizes the changing patterns of degradation behavior in PGA composites during degradation， and outlines the methods for regulating and evaluating PGA degradation performance. Furthermore， the paper discusses the problems and challenges associated with the regulation of PGA degradation.

This review provides a comprehensive overview of recent progress in the electrocatalytic upcycling of various plastic waste streams， including polyesters， polyolefins， and other common polymer types. It critically examines how advanced catalyst design strategies， such as modulation of electronic structure， interfacial engineering， optimization of surface morphology， and phase control， significantly influence reaction activity， selectivity， and stability. To overcome current technological barriers to scale⁃up， the paper outlines key future research directions： leveraging computational modeling for rational catalyst development， innovating efficient product separation and recovery methods， and engineering scalable reactor systems tailored for industrial implementation. Collectively， these approaches aim to establish a robust scientific and technological foundation for the industrial deployment of electrocatalytic plastic recycling and to accelerate the transition toward a circular plastics economy.

This review outlines the origin and compositional complexity of lignocellulosic biomass and critically evaluates current pretreatment approaches， categorized as physical （e.g.， mechanical grinding， microwave irradiation， ultrasonication）， chemical （e.g.， acid， alkali， TEMPO⁃mediated oxidation， deep eutectic solvents）， physicochemical （e.g.， steam explosion， hydrothermal treatment）， and biological methods. It also discusses their respective mechanisms， efficiencies， advantages， and limitations. Physical techniques are environmentally benign but often suffer from low deconstruction efficiency； chemical methods achieve high delignification or depolymerization yields yet may entail high reagent costs or environmental concerns； physicochemical processes are highly effective but typically demand energy⁃intensive， high⁃temperature/pressure conditions； biological pretreatments offer sustainability and specificity but require stringent control of operational parameters. The review further highlights the emerging applications of lignocellulosic⁃derived aerogels across diverse fields， including environmental remediation （e.g.， adsorption of heavy metal ions and organic pollutants）， energy storage， construction materials， and biomedicine. Finally， key scientific and technological challenges， such as scalability， structural stability， and cost⁃effectiveness， are identified， and future research directions are proposed to advance the development and practical deployment of lignocellulosic aerogels in a sustainable bioeconomy.

This paper presents a comprehensive review of the current quality landscape of plastic pipe products in China， focusing on product pass rates， risks associated with enterprise⁃specific standards， frequently failed test items， and underlying causes of non⁃compliance. The analysis indicates that intense market competition， characterized by high production volumes and low⁃price bidding， is a primary driver of quality issues. To meet aggressive cost targets， many manufacturers resort to reducing raw material expenses through various means， often compromising product performance and durability. Based on these findings， this review offers practical recommendations aimed at improving the overall quality and regulatory oversight of plastic pipe products in the Chinese market.