Polymer Technology Research Articles

Efficacy and Tolerance of a Polymeric Surfactant Technology-Based Cleanser for Clinically Diagnosed Sensitive Skin.

Cleansing is an important hygiene activity, necessary to prevent bacterial, fungal, yeast, and viral infection. However, in the presence of skin disease, cleansing can take on a new challenge: removing the sebum, sweat, externally applied substances, environmental debris, and organisms from the face without damaging the skin barrier. Since cleansers cannot easily distinguish between sebum and the intercellular lipids required to maintain skin integrity, unique cleansing technologies are necessary to provide mild cleansing for the many manifestations of sensitive skin. This 4-week clinical study aimed to evaluate the appropriateness of a cosmetic facial foaming gel cleanser with a polymeric surfactant technology in a diverse sensitive skin population. 85 subjects with sensitive skin due to eczema/atopic dermatitis, rosacea, acne, or cosmetic intolerance syndrome were evaluated via investigator grading, self-assessment questionnaire, noninvasive measurements, and digital photography. The foaming gel cleanser was well tolerated showing no significant increases in investigator-graded irritation endpoints. Sensitive skin subjects saw considerable reduction (P<0.05) in stinging, itching, burning, tightness, and overall sensitivity at 2 and 4 weeks. Improvements in smoothness, softness, clarity, radiance, and overall skin appearance, were observed by both the investigator and patients (P<0.05) at 2 and 4 weeks. The polymeric surfactant technology-based foaming gel cleanser provided a rich, foaming lather that felt gentle and left skin feeling comfortable. J Drugs Dermatol. 2024;23(10):889-893. doi:10.36849/JDD.8510.

Shape Memory Polymer Technology and Its Medical Applications

Abstract With actuation capabilities that respond to temperature or light, the potential uses for shape memory polymers (SMPs) in the biomedical arena are on the rise. This article describes current and potential future uses of SMPs for medical devices.

Emerging Trends in Engineering Polymers: A Paradigm Shift in Material Engineering

Emerging Trends in Engineering Polymers signify a pivotal transformation in material engineering, marking a departure from traditional materials towards innovative, multifunctional, and sustainable polymers. This review delineates the forefront of advancements in polymer materials, including high-performance, bio-based, biodegradable, innovative, and functional polymers. Highlighting their enhanced mechanical properties, thermal stability, and chemical resistance showcases these materials' pivotal role in driving technological progress. The exploration extends to advanced manufacturing techniques such as 3D printing, electrospinning, and the fabrication of polymer nanocomposites, underscoring their impact on customizing product properties and scaling production. Central to this discourse is the sustainability and environmental stewardship in the polymer sector, addressing recycling methodologies, the circular economy, and regulatory frameworks guiding sustainable practices. The review juxtaposes traditional and emerging recycling processes, illuminating the path toward more sustainable material cycles. Furthermore, it ventures into emerging applications across diverse sectors such as energy, electronics, healthcare, automotive, and aerospace, elucidating the transformative potential of engineering polymers in these domains. Challenges spanning technical, economic, environmental, and regulatory landscapes are critically examined, setting the stage for future directions in research and development. The review culminates in a forward-looking perspective, advocating for interdisciplinary collaboration and material science innovation to navigate modern engineering challenges' complexities. Through this comprehensive analysis, the review articulates a narrative of evolution and opportunity within engineering polymers, poised to redefine material engineering in the decades to come.

Exploring the impact of poly(sodium styrene sulfonate) dispersants’ architecture on their performance in coal water slurry preparation

In this work, the architecture of poly(sodium styrene sulfonate) (PSSNa) dispersants were flexibly tailored by various strategies. Three categories of PSSNa dispersants with different topologies were obtained, namely, linear structured PSSNa (1-A-PSSNa), three-arm star PSSNa (3-AS-PSSNa) and six-arm star PSSNa (6-AS-PSSNa). The molecular weights (Mn) of these dispersants were adjusted in the range of 3200–26,200 g/mol by varying the feeding ratio of monomer to initiator. In addition, the polydispersity index (PDI) of resultant dispersants were also varied by using different polymerization technologies, such as atom transfer radical polymerization (ATRP) and conventional free radical polymerization technique (RP). Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) verified these architecture parameters of resultant PSSNa dispersants. Afterwards, the impact of these architectural factors on the performance of PSSNa dispersants in coal water slurry (CWS) preparation were evaluated. The results revealed that with the Mn of dispersants increased from 9800 to 26,200 g/mol, the apparent viscosity of CWS increased by around 11 %. The comparison between dispersants with approximate Mn (26,200 and 26,900 g/mol) and very different PDI (1.27 and 2.25) indicated that wide PDI are favourable for the performance. This work also confirmed that the topology of dispersants has a significant impact on their performance. The maximum coal loaded can increase from 63.9 % to 64.3 % when 1-A-PSSNa dispersant was replaced by 6-AS-PSSNa. Meanwhile, these architectural factors have a limited impact on the fluid type of CWSs, as all CWSs obtained in this work were pseudoplastic fluids regardless of the used dispersants. The potential mechanism was investigated using various technologies, such as the measurements of zeta potentials, contact angles, and low-field nuclear magnetic resonance spectra. The results revealed that topologizing did not alter the interaction between dispersant and coal surface. However, due to the special features of topological polymers, they can grant adsorbed coal particles with enhanced electrostatic repulsion and steric hindrance, which facilitated the dispersion of coal particles.

Enhancing sludge thickening in continuous treatment using polymeric bubbles with cationic polymer P2900 and cocamidopropyl betaine.

Sludge thickening is a fundamental stage of treatment. This study investigated the application, in continuous treatment, of polymeric bubbles produced with cationic polymer P2900 and cocamidopropyl betaine (CAPB), a zwitterionic surfactant. The proposed reagent combination aims to form aerated flakes, solid waste structures, and rapidly rising air bubbles, ideal for treatments in compact units. Using this combination, it was possible to achieve a total solids concentration of 45% with the modified bubbles and 25% with the conventional water treatment. This level of thickening occurred under the following operating conditions: initial total solids (TS) concentration of 10g L-1, a flow rate of 5 L min-1, saturation pressure (psat) of 3atm, and polymer dosage of 10mg (gTS)-1. The suggested mechanism of action involves the adhesion of P2900 molecules to CAPB at the air/water interface, forming a lining on the bubble surface. Additionally, polymerized species form due to the residual aluminum (Al) in the sludge, which would occur during flocculation in the helical tubular flocculator (HTF), adsorbing the micelles and bubbles of CAPB. The critical micellar concentration (CMC) of CAPB was 0.26mmol L-1. Polymeric bubble technology can provide an efficient and cost-effective approach to sludge thickening in continuous treatment.

Модификация твердофазной полимерной поверхности путём прививки акриловых мономеров

Graft copolymerization onto a solid polymer surface is an effective tool for its modification. A large number of works have been published and require systematization. A search and review of English-language scientific literature devoted to the graft copolymerization of acrylic monomers onto a polymeric solid-phase surface have been carried out. Grafting onto plates and films, as well as fibers and colloidal particles, is considered. It has been revealed that the most popular substrates for graft copolymerization are, besides polyethylene, propylene and polyethylene terephthalate; polyurethanes, polyfluoroethylenes, rubbers, etc. Graft polymerization mainly proceeds on amorphous areas of the substrate and does not destroy the crystalline phase. It is possible to use the methods of controlled radical polymerization (ATRP, RAFT). Of the acrylic monomers, acrylic and methacrylic acids, glycidyl acrylate and glycidyl methacrylate, and others have been used, while the main method has been UV photopolymerization with an initiator–benzophenone. Of the three aliphatic ketones (acetone, methyl ethyl ketone and methyl propyl ketone), acetone has been the best solvent. Cophotoinitiators have been also used (a synergistic effect was observed), corona discharge, gamma radiation (60Co), ozone and plasma treatment, and a supercritical CO2 medium. The degree of grafting has been controlled by changing the soaking time in the monomer, pressure, concentration of monomer and initiator in the liquid phase, reaction temperature and reaction time. A new technology of graft polymerization with photopatterning has also been proposed. Problems of graft polymerization in terms of surface modification of polymer materials (hydrophilization of the surface, improving paintability and wettability, enhancing adhesion to certain surfaces, biocompatibility) are touched upon, and possible areas of their application are outlined.

Comparative life cycle assessment of PBAT from fossil-based and second-generation generation bio-based feedstocks

With the increasing demand for plastics, plastic pollution is growing rapidly. A significant amount of plastic has leaked into the environment, leading to severe environmental issues. Biodegradable plastics are considered promising alternatives to conventional durable plastics, and the environmental impacts of biodegradable plastics have received increasing attention. Poly (butylene adipate-co-terephthalate) (PBAT) is a commercial and cost-competitive biodegradable polymer and has been applied in the packaging and agriculture sectors. The environmental performances of PBAT with second-generation feedstocks from forestry waste have been rarely investigated. Since China is the leading global producer and exporter of PBAT polymer, Chinese cradle-to-gate life cycle inventories of PBAT were compiled in this study. A comparative life cycle assessment (LCA) was conducted to explore the potential for environmental performance of PBAT with second-generation bio-based feedstock compared to fossil-based PBAT and conventional plastics. The results showed that feedstocks contributed to more than 70 % of 18 environmental impact categories of fossil-based PBAT. In comparison, PBAT with second-generation bio-based feedstock reduces the environmental loads in 16 impact categories by 15–85 %, and renewable energy substitution has the potential to reduce environmental impacts by 10 %. Bio-based PBAT performs better than PVC, PP, HDPE, LDPE, and PET in 16 impact categories by 15–80 %. Bio-based PBAT has GWP of 3.72 kg CO2 eq, which is 37 % lower than fossil-based PBAT (5.89 kg CO2 eq) and 18–32 % lower than conventional plastics. Since feedstock dominates the environmental performance of PBAT, the development of biomanufacturing technologies for bio-based polymers and chemicals could significantly improve environmental performance of biodegradable plastics and promote the sustainable development of the plastic industry. Results could serve as the basis for environmental impact and mitigation strategies for biodegradable plastics with bio-based feedstocks, as well as the sustainable development of the PBAT industry.

A Complete Appraisal of Polymeric Micelle-Based Nanocarrier for Targeting Breast Cancer: Recent Strategies and Advancements

Aim/Objective: Polymeric micelle-based drug delivery systems have emerged as a beacon of hope in the challenging landscape of breast cancer therapy. This review aimed to explore the recent advancements and promising developments in the field, offering an in-depth analysis of their potential and challenges. The significance of this study lies in providing a comprehensive examination of the current advances in polymeric micelles technology, which have the potential to improve the efficiency and specificity of breast cancer therapy while minimizing adverse events. Methods: Polymeric micelles offer a revolutionary therapy by encapsulating therapeutic agents, allowing for controlled drug release and the precise targeting of malignant cells, while lowering systemic toxicity. Recent advances have focused on enhancing targeting strategies, including active and passive targeting, to increase the specificity of polymeric micelle-based therapies. A systematic review of literature was carried out using databases, like PubMed, Scopus, and Web of Science, which included papers published between 2010 and 2023. The selection criteria of the literature focused on the drug-loading capabilities and targeting strategies of the polymeric micelles, which could be advantageous for breast cancer treatment. Results: Clinical drug approaches leverage the versatility of micelles to co-deliver multiple agents, addressing the multifaceted nature of breast tumors and combating drug resistance. Additionally, polymeric micelles are finding applications in breast cancer diagnostics and imaging, enabling early detection and precise monitoring. The journey of polymeric micelle-based breast cancer therapy extends to formulation and engineering, preclinical and clinical studies, and confronts regulatory and commercialization challenges. However, the horizon is illuminated by emerging technologies, like personalized medicine, biomarker-driven targeting, and integration with novel therapies, promising a future where breast cancer treatment is tailored to individual patients and marked by improved efficacy and reduced side effects. Conclusion: In conclusion, this review underscores the transformative potential of polymeric micelle- based delivery systems in breast cancer therapy.

Sustainable engineering polymer composites fabricated using delignified bamboo fiber as reinforcement and walnut shell powder as filler

Developing sustainable engineering materials using renewable resources and agro-wastes represents an effective method for reducing carbon emissions and environmental pollution. In this study, a novel approach to fabricating high-performance biomass-based polymer composites was presented. Specifically, partially delignified bamboo fiber (DBF) and walnut shell powder (WSP) were incorporated into the matrix, namely melamine-hexamethylenediamine-urea (MHU) resin which was previously known for its excellent interfacial compatibility. Mechanical property investigations show that the DBF, acting as the reinforcement, provided the hybrid composites with high flexural and tensile strength up to 220 and 120 MPa, respectively, greatly surpassing those of commercial wood-plastic composites, wood-based composites, and natural wood, making them promising structural materials. As the filler, walnut shell powder endowed the composites with high hardness (Shore D > 90) and an appealing mirror-like surface gloss. Owing to the protection provided by the MHU matrix, the composite containing 38 % MHU exhibited outstanding flame retardancy (UL 94-V0 grade), which was further supported by cone calorimeter test (CCT) results. An unexpected and intriguing finding is that the composites exhibited fluorescence under UV irradiation. The rare silvery-grey fluorescence color imparted self-anticounterfeiting property to the composites. This study demonstrated the significant potential of bamboo fiber and walnut shell in the development of sustainable engineering materials.

The development of polymers and fibers: an interview with Stephen Cheng.

Polymer and fiber science has evolved significantly since the 1920s, with polymers becoming integral to both industry and daily life. China's fiber research, initiated in the 1950s, has made substantial societal and technological contributions, particularly in chemical fibers. How will future advancements in polymers and fibers address ongoing challenges and drive further innovation? NSR spoke to Prof. Stephen Cheng, a member of the National Academy of Engineering (U.S.) and former Dean of the College of Polymer Science and Polymer Engineering at the University of Akron. He is currently Dean and Honorable Professor at South China University of Technology. His research interests center on the condensed states in polymers, liquid crystals, surfactants and hybrid materials, focusing on the interactions, responses, dynamics and structures of materials at varying lengths, energy and timescales, in which the material itself embodies the technology.

Recent Advances in the Development of 1,4-Cyclohexanedimethanol (CHDM) and Cyclic-Monomer-Based Advanced Amorphous and Semi-Crystalline Polyesters for Smart Film Applications.

Polyester-based advanced thin films have versatile industrial applications, especially in the fields of textiles, packaging, and electronics. Recent advances in polymer science and engineering have resulted in the development of advanced amorphous and semi-crystalline polyesters with exceptional performance compared to those of conventional polymeric films. Among these, 1,4-cyclohexanedimethanol (CHDM) and cyclic-monomer-based polyesters have gained considerable attention for their exceptional characteristics and potential applications in smart films. This review article provides a comprehensive overview of the recent advances in the synthesis, characterization, and applications of CHDM and cyclic-monomer-based advanced polymers for smart film applications. It discusses the structure-property relationships of these innovative polyesters and highlights their unique characteristics, including thermal, mechanical, and barrier characteristics. Furthermore, this article also emphasizes the solution, melt, and solid-state polymerizations of the polymers. Special emphasis is placed on the influence of the addition of a second diol or second diacid on the performance characteristics of synthesized polyesters/copolyesters to explore their versatile industrial applications. Additionally, the impact of the stereochemistry of the monomers is explored to optimize the characterization of polyesters suitable for industrial applications. Furthermore, this article explores the potential of these advanced polyesters to be considered as materials for smart film applications, especially in the field of flexible electronics. Finally, this article examines the challenges and future recommendations for the development of CHDM and cyclic-monomer-based polyesters for smart film applications. It discusses potential avenues for further research, including in-depth studies for the synthesis and characterization of polyesters, the development of sustainable and biodegradable alternatives to cyclic monomers, alternative green approaches for the synthesis of polymers, etc. This review article provides valuable insight for researchers in academia and industry who are working in the fields of polymer science and materials engineering.

An Opportunity for Synergizing Desalination by Membrane Distillation Assisted Reverse-Electrodialysis for Water/Energy Recovery.

Industry, agriculture, and a growing population all have a major impact on the scarcity of clean-water. Desalinating or purifying contaminated water for human use is crucial. The combination of thermal membrane systems can outperform conventional desalination with the help of synergistic management of the water-energy nexus. High energy requirement for desalination is a key challenge for desalination cost and its commercial feasibility. The solution to these problems requires the intermarriage of multidisciplinary approaches such as electrochemistry, chemical, environmental, polymer, and materials science and engineering. The most feasible method for producing high-quality freshwater with a reduced carbon footprint is demanding incorporation of industrial low-grade heat with membrane distillation (MD). More precisely, by using a reverse electrodialysis (RED) setup that is integrated with MD, salinity gradient energy (SGE) may be extracted from highly salinized MD retentate. Integrating MD-RED can significantly increase energy productivity without raising costs. This review provides a comprehensive summary of the prospects, unresolved issues, and developments in this cutting-edge field. In addition, we summarize the distinct physicochemical characteristics of the membranes employed in MD and RED, together with the approaches for integrating them to facilitate effective water recovery and energy conversion from salt gradients and freshwater.

Reversible Addition-Fragmentation Chain-Transfer Polymerization in Supercritical CO2: A Review.

The development of cleaner, more environmentally friendly processes in polymerization technology is crucial due to the prevalent use of volatile organic solvents (VOCs), which are harmful and toxic. Future regulations are likely to limit or ban VOCs. This review explores the use of supercritical solvents, specifically supercritical CO2 (scCO2), in polymerization processes. The study focuses on reversible addition-fragmentation chain-transfer (RAFT) induced homo-polymerization of various monomers using specific chain transfer agents (CTAs) in scCO2. RAFT polymerization, a reversible deactivation radical polymerization (RDRP) polymerization, relies heavily on the choice of CTA, which significantly influences the dispersity and molar mass of the resulting polymers. Stabilizers are also crucial in controlling product specifications for polymerizations in supercritical CO2, except for fluor-based polymers, although they must be removed and preferably recycled to ensure product purity and sustainability. The review notes that achieving high molar mass through RAFT polymerization in scCO2 is challenging due to solubility limits, which lead to polymer precipitation. Despite this, RAFT polymerization in scCO2 shows promise for sustainable, circular production of low molar mass polymers, although these cannot yet be fully considered green products.

Polymeric Microneedle Drug Delivery Systems: Mechanisms of Treatment, Material Properties, and Clinical Applications-A Comprehensive Review.

Our comprehensive review plunges into the cutting-edge advancements of polymeric microneedle drug delivery systems, underscoring their transformative potential in the realm of transdermal drug administration. Our scrutiny centers on the substrate materials pivotal for microneedle construction and the core properties that dictate their efficacy. We delve into the distinctive interplay between microneedles and dermal layers, underscoring the mechanisms by which this synergy enhances drug absorption and precision targeting. Moreover, we examine the acupoint-target organ-ganglion nexus, an innovative strategy that steers drug concentration to specific targets, offering a paradigm for precision medicine. A thorough analysis of the clinical applications of polymeric microneedle systems is presented, highlighting their adaptability and impact across a spectrum of therapeutic domains. This review also accentuates the systems' promise to bolster patient compliance, attributed to their minimally invasive and painless mode of drug delivery. We present forward-looking strategies aimed at optimizing stimulation sites to amplify therapeutic benefits. The anticipation is set for the introduction of superior biocompatible materials with advanced mechanical properties, customizing microneedles to cater to specialized clinical demands. In parallel, we deliberate on safety strategies aimed at boosting drug loading capacities and solidifying the efficacy of microneedle-based therapeutics. In summation, this review accentuates the pivotal role of polymeric microneedle technology in contemporary healthcare, charting a course for future investigative endeavors and developmental strides within this burgeoning field.

Advancement of constant and progressive load multi‐cycle indentation method on surface properties characterization of polymers

AbstractIn recent years, polymers have been popular in industrial applications due to their lightweight, corrosion‐resistant, improved surface polish, ease of manufacturing, cost‐effectiveness, and so forth. Similarly, micro/nano‐indentation has gained popularity as a technique for assessing the surface mechanical characteristics of polymers. The present study conducted comprehensive experiments using cyclic micro‐indentation on engineering polymers, specifically poly‐ether‐ether‐ketone (PEEK), poly(methyl methacrylate) (PMMA), and poly(tetra‐fluoroethylene) (PTFE). An appropriate and optimal indentation method has been proposed after analyzing the behavior and significance of all the input parameters in evaluating the properties. Both constant load multi‐cycle (CLMC) and progressive load multi‐cycle (PLMC) were considered for this investigation. A comparative evaluation has been conducted to assess two multi‐cycle tests on these materials. From the analysis of the input parameters, including maximum loads, loading and unloading rates, and the number of cycles, the unloading rate and indentation cycle are crucial factors in determining hardness (H) and elastic modulus (E). Increasing the loading rates leads to an increase in H and a reduction in E for all three materials. This effect arises from the thermal effect, which is characterized by the creep modulus and a closed hysteresis loop. Employing the holding duration and multiple cycle data in constant load multi‐cycle can significantly influence the creep behavior and use of the hysteresis loop for fatigue behavior. Similarly, a progressive load multi‐cycle indentation with a force greater than 0.5 N and a minimum of five cycles is the most accurate approach for evaluating surface mechanical parameters.

Femtosecond laser fabrication of nanopillar arrays for Surface-Enhanced Raman scattering substrates

This work presents a femtosecond laser fabrication method for precision-engineered nanopillar arrays, applicable for surface-enhanced Raman scattering (SERS) substrates. The proposed method consists of two steps: (1) fabrication of nanopillar arrays using femtosecond laser-induced two-photon polymerization (TPP) technology; and (2) deposition of Ag nanoparticles on the fabricated nanopillar arrays. Nanopillar arrays of the proposed SERS substrates are optimized with geometrical parameters of diameter, height, spacing, and arrangement. A limit of detection (LOD) down to 10-7 mol/L for Rhodamine 6G solution is achieved and the enhancement factor is estimated to be up to 2 × 103. The experimental results indicate that the proposed SERS substrates have potential applications in biomedical detection, food safety monitoring, and quality control.

Abalone shells bioenhanced carboxymethyl chitosan/collagen/PLGA bionic hybrid scaffolds achieving biomineralization and osteogenesis for bone regeneration

Inspired by the formation of natural abalone shells (AS) similar to calcium salt deposition in human orthodontics, AS is used as an emulsifier in the scaffold to solve the problem of coexistence of natural and synthetic polymers and promote new bone formation. In this study, AS-stabilized and reinforced carboxymethyl chitosan/collagen/PLGA porous bionic composite scaffolds (AS/CMCS/Col/PLGA) were fabricated through the emulsion polymerization and bionic hybrid technology. As the addition of AS increased from 0.75 to 3.0 wt%, homogeneous distribution of flower-like particles could be observed on the inner surface of the scaffold, and its mechanical properties were improved. Particularly, 3.0 wt% AS-doped scaffolds (S3 and C + S3) exhibited excellent inorganic mineral deposition and osteoblast proliferation and differentiation abilities in vitro. In a SD rat calvarial defect model, they effectively promoted new bone formation in the defect and accelerated expression of osteogenic-angiogenic related proteins (COLI, OCN, VEGF). By virtue of its combined merits including good mechanical properties, inducing mineralization crystallization and facilitating osteogenesis, the 3.0 wt% AS-doped scaffold promises to be employed as a novel bone repair material for bone tissue regeneration.

A simple approach to design fabric with flame-retardant and pattern function

The study of fabrics’ flame retardant properties has always been a hot topic in the field of textiles. In this paper, a flame-retardant fabric with a sandwich structure was obtained by combining hydrogel patch method and in-situ polymerization technology via a two-step method. The thermogravimetric analysis (TGA) showed that the hydrogel could improve PLA materials’ thermal stability effectively. The hydrogel treated fabrics’ limiting oxygen index (LOI) value increased from 21.05 % to 80.00 %. The cone calorimeter test demonstrated that the pHRR and THR of the hydrogel treated fabrics decreased to 51.48 % and 55.97 %, respectively. After adding a mixture of ferric oxide and mica during the in-situ polymerization of the hydrogel, the pHRR and THR of the obtained fabric decreased to 43.77 % and 46.00 %, respectively, compared to the original PLA fabric. Furthermore, the mechanical strength test showed that the introduction of hydrogel patch had almost no effect on the mechanical properties of PLA materials. In addition, by using the way that metal ions can be arranged into a special array on the magnetic induction line, under the synergistic effect between ferric oxide and mica, the array formed by the ferric oxide particles on the magnetic induction line was designed with a series of patterns on its surface. Finally, a kind of textile with flame retardant properties and different patterns was obtained.

Degradable living plastics programmed by engineered spores.

Plastics are widely used materials that pose an ecological challenge because their wastes are difficult to degrade. Embedding enzymes and biomachinery within polymers could enable the biodegradation and disposal of plastics. However, enzymes rarely function under conditions suitable for polymer processing. Here, we report degradable living plastics by harnessing synthetic biology and polymer engineering. We engineered Bacillus subtilis spores harboring the gene circuit for the xylose-inducible secretory expression of Burkholderia cepacia lipase (BC-lipase). The spores that were resilient to stresses during material processing were mixed with poly(caprolactone) to produce living plastics in various formats. Spore incorporation did not compromise the physical properties of the materials. Spore recovery was triggered by eroding the plastic surface, after which the BC-lipase released by the germinated cells caused near-complete depolymerization of the polymer matrix. This study showcases a method for fabricating green plastics that can function when the spores are latent and decay when the spores are activated and sheds light on the development of materials for sustainability.

High-performance thermoplastic nanocomposites for aerospace applications: A review of synthesis, production, and analysis

Thermoset polymers are cured under natural or synthetic created conditions and retain their solid form when exposed to heat. Unlike thermosets, thermoplastics melt when exposed to heat after production. Thermoplastics are preferred as raw materials because they can be easily shaped after production, have a high shelf life and are recyclable. In this regard, the prominence of high-performance engineering polymers in recent years has led to the preference of alternative polymers to thermosets. High-performance engineering thermoplastics include thermoplastics such as polyphenylene-sulfide (PPS), polyether-ether-ketone (PEEK), polyether-ketone-ketone (PEKK), polyphenylene-ether, polysulfone,polyoxadiazole, polyimide, polyether-amide, polyether-amide-imide, polynaphthalene, and polyamide-imide. These polymers exhibit application potential in aerospace, defense, automotive, marine, energy, and medical sectors. In challenging conditions such as high pressure, temperature, and corrosive environments, they possess high service temperatures, enhanced mechanical and physical properties, preferable chemical resistance as well as out-of-autoclave and rapid processing properties. In this review article, nanomaterial production methods (bottom-up and top-bottom) are mentioned. In the following sections, PPS, PEEK, and PEKK thermoplastics are explained, and carbon- and boron-based nano additives used in constructing nanocomposites are investigated. In the last section, PPS, PEKK, and PEEK polymer nanocomposites are investigated.