Cross-linking Of Chains Research Articles

Radiation Induced Changes in Makrofol PCVM Polycarbonate

Makrofol PCVM is a sort of Makrofol polycarbonate solid state nuclear track detector. It is worth mentioning that this paper is almost the first one that deals with the modification of the optical properties of this type of Makrofol under the effect of laser radiation. Samples from Makrofol PCVM were exposed to infrared pulsed laser with different fluences ranging from 15 to 125 J/cm2 . UV spectroscopic technique was used to obtain knowledge about the optical parameters that describe the samples under study. The changes of Urbach energy (Eu ), optical band gap (Eg ) and refractive index (n) with the laser fluence were investigated. Both Eu and n increased with increasing the fluence up to 125 J/cm2 , associated with a decrease of Eg values. These trends were assigned to the predominance of chain crosslinking that damaged the crystalline portion in the Makrofol polymer. Additionally, we used the CIE technique to calculate the color differences between the noncoloured pristine and the irradiated samples. The crosslinking created color centers that produced color difference between the exposed films and the uncolored pristine Makrofol film. The color difference was significant as the values of ΔE were greater than 5. This optimized the Makrofol polymer to be used in dosimetric applications.

Intrinsically stretchable and self-healable tribotronic transistor for bioinspired e-skin

Skin inspired sensory electronics are preferable to be stretchable and self-healable to satisfy the prolonged wearing demands. Here, we reported an intrinsically stretchable and self-healable tribotronic transistor for bioinspired e-skin, in which the output current can be modulated by external contact electrification. By dynamic non-covalent crosslinking and self-bonding of polymer chains, the device can be stretched to 50% for more than 500 cycles without significant performances loss, and restored at room temperature after multiple cycles of a complete cut with high healing efficiency (>99%). Moreover, the device has high skin compatibility for multifunctional sensing, such as detection of contact and proximity. Finally, a bioinspired e-skin operating under deformations/damages is demonstrated for robot control and grasping objects. This work has not only presented a biomimetic tribotronic transistor for human and robot skins, but also exhibited broad prospects for future robust tribotronics in wearable electronics, robotics, and bionics.

How Particle Deformability Influences the Surfactant Distribution in Colloidal Polymer Films.

The distribution of surfactants in waterborne colloidal polymer films is of significant interest for scientific understanding and defining surface properties in applications including pressure-sensitive adhesives and coatings. Because of negative effects on appearance, wetting, and adhesion, it is desirable to prevent surfactant accumulation at film surfaces. The effect of particle deformation on surfactant migration during film formation was previously investigated by Gromer et al. through simulations, but experimental investigations are lacking. Here, we study deuterium-labeled sodium dodecyl sulfate surfactant in a poly(butyl acrylate) latex model system. The particle deformability was varied via cross-linking of the intraparticle polymer chains by differing extents. The cross-linker concentration varied from 0 to 35 mol % in the copolymer, leading to a transition from viscoelastic to elastic. Ion beam analysis was used to probe the dry films and provide information on the near-surface depth distribution of surfactant. Films of nondeformable particles, containing the highest concentration of cross-linker, show no surfactant accumulation at the top surface. Films from particles partially deformed by capillary action show a distinct surfactant surface layer (ca. 150 nm thick). Films of coalesced particles, containing little or no cross-linker, show a very small amount of surfactant on the surface (ca. 20 nm thick). The observed results are explained by considering the effect of cross-linking on rubber elasticity and applying the viscous particle deformation model by Gromer et al. to elastically deformed particles. We find that partially deformed particles allow surfactant transport to the surface during film formation, whereas there is far less transport when skin formation acts as a barrier. With elastic particles, the surfactant is carried in the water phase as it falls beneath the surface of packed particles. The ability to exert control over surfactant distribution in waterborne colloidal films will aid in the design of new high-performance adhesives and coatings.

Hydrogels as promising carriers for the delivery of food bioactive ingredients.

The burden of public health challenges associated with the western dietary and living style is growing. Nutraceuticals have been paid increasing attentions due to their effects in promotion of health. However, in the gastrointestinal (GI) tract, the nutraceuticals suffer from not only the harsh acidic environment of the stomach and a variety of digestive enzymes, but also the antibacterial activity of intestinal bile salts and the action of protease from the gut microbiota. The amount of the nutraceuticals arriving at the sites in GI tract for absorption or exerting the bioactivities is always unfortunately limited, which puts forward high requirements for protection of nutraceuticals in a certain high contents during oral consumption. Hydrogels are three-dimensional polymeric porous networks formed by the cross-linking of polymer chains, which can hold huge amounts of water. Compared with other carries with the size in microscopic scale such as nanoparticle and microcapsules, hydrogels could be considered to be more suitable delivery systems in food due to their macroscopic bulk properties, adjustable viscoelasticity and large spatial structure for embedding nutraceuticals. Regarding to the applications in food, natural polymer-based hydrogels are commonly safe and popular due to their source with the appealing characteristics of affordability, biodegradability and biocompatibility. Although chemical crosslinking has been widely utilized in preparation of hydrogels, it prefers the physical crosslinking in the researches in food. The reasonable design for the structure of natural polymeric hydrogels is essential for seeking the favorable functionalities to apply in the delivery system, and it could be possible to obtain the enhanced adhesive property, acid stability, resistant to bile salt, and the controlled release behavior. The hydrogels prepared with proteins, polysaccharides or the mix of them to deliver the functional ingredients, mainly the phenolic components, vitamins, probiotics are discussed to obtain inspiration for the wide applications in delivery systems. Further efforts might be made in the in situ formation of hydrogels in GI tract through the interaction among food polymers and small-molecular ingredients, elevation of the loading contents of nutraceuticals in hydrogels, development of stomach adhesive hydrogels as well as targeting modification of gut microbiota by the hydrogels.

Elucidating the Role of Alkoxy Radicals in Polyethylene Radio-Oxidation Kinetics

Polyethylene is a widely used polymer and a prototypical polyolefin. Understanding degradation mechanisms at the atomic scale leading to oxidation under the effect of temperature and/or irradiation is crucial for many long-term applications. Here, we focus on a subset of reactions belonging to the generally assumed radio-oxidation reaction scheme and involving alkoxy radicals. We follow a theoretical approach based on density functional theory, in order to assess the role of these species, which are short lived and thus hard to detect experimentally. For every considered reaction, we calculate the reaction enthalpy and the energy barrier, and we evaluate the influence of the local atomic environment, taking advantage of a model surface of a crystalline lamella which mimics the interface between crystalline and amorphous zones. Our results suggest that in certain conditions, the kinetic pathway can bypass the formation of hydroperoxides. The concentrations of alkoxy and peroxy radicals during radio-oxidation and their ratio are important parameters controlling the predominance of chain scission or crosslinking in the polymer. The data presented here constitute part of a database that can be used to set up kinetic simulations based on homogeneous chemical kinetics or Monte Carlo algorithms.

Effect of stoichiometry on chemical structure, dielectric and mechanical properties of epoxy resin under gamma irradiation

The chemical and physical properties of diglycidyl ethers of bisphenol-A (DGEBA)/2,2'-(ethylenedioxy) bis(ethylamine) (EDBA) epoxy resins with different stoichiometric ratios under gamma irradiation have been investigated. Fourier transform infrared (FTIR) spectroscopy results indicated that a mass of amines and oxidized carbonyl-containing products were generated during the irradiation process. Most products for amine-rich DGEBA/EDBA systems were amides. Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) results demonstrated that chain scission predominated during irradiation for the amine-rich system, while chain cross-linking predominated for the epoxy-rich system. The dielectric relaxation behaviours indicated that the α relaxation behaviours broadened considerably with an increasing irradiation dose, demonstrating an increasing spatial heterogeneity of the crosslinked networks. The compressive yield strengths showed a monotonous linear increase with irradiation dose. However, due to the different cross-linking networks, the yield strains showed converse trends for amine-rich and epoxy-rich systems under gamma irradiation.

Robust Antibacterial Activity of Xanthan-Gum-Stabilized and Patterned CeO2-x-TiO2 Antifog Films.

Increased occurrence of antimicrobial resistance leads to a huge burden on patients, the healthcare system, and society worldwide. Developing antimicrobial materials through doping rare-earth elements is a new strategy to overcome this challenge. To this end, we design antibacterial films containing CeO2-x-TiO2, xanthan gum, poly(acrylic acid), and hyaluronic acid. CeO2-x-TiO2 inks are additionally integrated into a hexagonal grid for prominent transparency. Such design yields not only an antibacterial efficacy of ∼100% toward Staphylococcus aureus and Escherichia coli but also excellent antifog performance for 72 h in a 100% humidity atmosphere. Moreover, FluidFM is employed to understand the interaction in-depth between bacteria and materials. We further reveal that reactive oxygen species (ROS) are crucial for the bactericidal activity of E. coli through fluorescent spectroscopic analysis and SEM imaging. We meanwhile confirm that Ce3+ ions are involved in the stripping phosphate groups, damaging the cell membrane of S. aureus. Therefore, the hexagonal mesh and xanthan-gum cross-linking chains act as a reservoir for ROS and Ce3+ ions, realizing a long-lasting antibacterial function. We hence develop an antibacterial and antifog dual-functional material that has the potential for a broad application in display devices, medical devices, food packaging, and wearable electronics.

One facile route to prepare high‐strength natural rubber through a green cardanol modification technology

AbstractA new modification strategy of natural rubber (NR) with high efficiency and environmental protection is proposed to get a high‐strength natural rubber (HSNR) by wetly modifying the natural latex with cardanol emulsified by emulsifier fatty alcohol polyoxyethylene ether sodium sulfate (AES) first and then short‐term high‐temperature treatment. The obtained HSNR was characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. Moreover, the influences of the amount of cardanol on the crystallization behavior, processability, and physicomechanical properties were also studied. The results indicated that HSNR has a higher molecular weight, gel content, Mooney viscosity, initial plastic value, and elastic modulus, exhibiting good thermal stability and high glass transition temperature. Markedly, HSNR vulcanizates had excellent mechanical strength and thermo‐oxidative aging resistance when the optimum dosage of cardanol was 1 phr. Further discussion revealed that cardanol could effectively modify NR and enhance comprehensive properties by promoting the crosslinking of molecular chains of NR and introducing phenol, which contributed to the potential value in the application field of replacing ribbed smoked sheets.

Injectable and Self-Invigorating Hydrogel Applications in Dentistry and Periodontal Regeneration: A Literature Review.

Hydrogels are thought of as unique polymers utilized to build new materials, and two key factors that impact their features are their hydrophilicity and the degree of cross-linking of the polymer chains. An injectable hydrogel is based on the hypothesis that certain biomaterials can be injected into the body as a liquid and progressively solidify there. The scientific research community was intrigued and interested by its discovery. The hydrophilic polymers that are used to make hydrogels can typically be split into two groups: natural polymers derived from tissues or other sources of natural materials, and synthetic polymers produced by combining principles from organic chemistry and molecular engineering. A variety of organic and synthetic biomaterials, such as chitosan, collagen or gelatin, alginate, hyaluronic acid, heparin, chondroitin sulfate, polyethylene glycol, and polyvinyl alcohol, are used to generate injectable hydrogels. A promising biomaterial for the therapeutic injection of cells and bioactive chemicals for tissue regeneration in both dentistry and medicine, injectable hydrogels have recently attracted attention. Since injectable scaffolds can be implanted with less invasive surgery, their application is seen as a viable strategy in the regeneration of craniofacial tissue. Treatment for periodontitis that effectively promotes periodontal regeneration involves injecting a hydrogel that contains medications with simultaneous anti-inflammatory and tissue-regenerating capabilities. The advantages of injectable hydrogel for tissue engineering are enhanced by the capability of three-dimensional encapsulation. A material's injectability can be attributed to a variety of mechanisms. The hydrogels work well to reduce inflammation and promote periodontal tissue regeneration.

A novel alternative to free oil remediation and recovery: Foamy absorbents designed from low molecular paraffinic waste

This study focuses on preparing porous, hydrophobic, and oleophilic hydrocarbon-based foams applicable for removing free oils from water surfaces. Paraffinic waste material generated during industrial production of low-density polyethylene (Qatar Petrochemical Company) was used for the preparation of foamy, elastic structures through crosslinking of short aliphatic chains by dicumyl peroxide and foaming by 1,1′-azobiscarbamide. The porosity of the foam determined by computer microtomography was 58.9%, and the bulk density was 0.42 g.cm−3. The sorption ability of the foam was tested using diesel oil, motor oil, and heavy crude oil. The absorption capacity of foam was characterized as the ratio between the mass of oil absorbed by the foam and the mass of a neat foam (Sw) and as the ratio between the volume of oil absorbed by the foam and the volume of a neat foam (Sv). The absorption capacities of the new foam reported in this study (referred to here as Qwax foam) are 6.6 ± 0.3 g/g, or 3.3 ± 0.2 cm3/cm3 for diesel oil, 3.9 ± 0.4 g/g or 1.9 ± 0.3 cm3/cm3 for motor oil, and 3.4 ± 0.2 g/g or 1.4 ± 0.4 cm3/cm3 for crude oil. To compare the sorption ability of Qwax foam with some standard foams, the absorption capacities of highly porous commercial polyurethane (PU) and melamine (MA) foams were investigated under the same conditions. These foams showed much higher sorption capacity considering the Sw parameter as a reference; however, there was a lower sorption capacity compared to parameter Sv. In the last paragraph, the suitability and the relevancy of parameters Sw and Sv for a comparison of the absorption capacity of foams were theoretically analyzed.

Application of Multiple Length Cross-linkers to the Characterization of Gaseous Protein Structure.

The speed, sensitivity, and tolerance of heterogeneity, as well as the kinetic trapping of solution-like states during electrospray, make native mass spectrometry an attractive method to study protein structure. Increases in the resolution of ion mobility measurements and in mass resolving power and range are leading to the increase of the information content of intact protein measurements and an expanded role of mass spectrometry in structural biology. Herein, a suite of different length noncovalent (sulfonate to positively charged side chain) cross-linkers was introduced via gas-phase ion/ion chemistry and used to determine distance restraints of kinetically trapped gas-phase structures of native-like cytochrome c ions. Electron capture dissociation allowed for the identification of cross-linked sites. Different length linkers resulted in distinct pairs of side chains being linked, supporting the ability of gas-phase cross-linking to be structurally specific. The gas-phase lengths of the cross-linkers were determined by conformational searches and density functional theory, allowing for the interpretation of the cross-links as distance restraints. These distance restraints were used to model gas-phase structures with molecular dynamics simulations, revealing a mixture of structures with similar overall shape/size but distinct features, thereby illustrating the kinetic trapping of multiple native-like solution structures in the gas phase.

SPEEK-based composite proton exchange membrane regulated by local semi-interpenetrating network structure for vanadium flow battery

To solve the trade-off between proton conduction and ion permeation of proton exchange membrane, we develop an amphoteric composite membrane composed of sulfonated poly(ether ether ketone) containing imidazole chains (SPEEK-IM) and side-chain sulfonated polyethersulfone having covalently cross-linked perfluoroalkyl chains (CSPF). Through the local semi-interpenetrated network regulated by imidazole and sulfonic acid groups in the CSPF, a synergistic proton transport channel is constructed in the SPEEK-IM/CSPF membrane. The proton conductivity (31.2 mS cm−1) and ion selectivity (49.5 × 103 S min cm−3) of SPEEK-IM/CSPF-10 show an outstanding improvement against Nafion 212 (28.0 mS cm−1 and 3.0 × 103 S min cm−3). SPEEK-IM/CSPF-10 demonstrates a superior energy efficiency, 74.2%, at 200 mA cm−2, which is much higher than that of SPEEK (58.7%), SPEEK-IM (64.7%), and Nafion 212 (64.0%). Meanwhile, a 48.6% charge capacity retention after 200 charge-discharge cycles at 150 mA cm−2 and 600-time cycle stability further support the formed local cross-linking network and acid-base interaction guarantee the mechanical and chemical stability of the composite membrane. This study demonstrates that synergistic proton conduction channels regulated by covalently crosslinked structure and semi-interpenetrating network can explore a promising high-performance composite membrane for the VFB application.

Color-phase readout radiochromic photonic crystal dosimeter

<h2>Summary</h2> The development of power-free, wide-range, and real-time visible radiation dosimeters is highly desirable but challenging. Here, we report a new dosimetry concept based on the continuous and linear Bragg wavelength shift of photonic crystals in response to X-ray or γ-ray radiation. As a proof of concept, three distinct photonic crystal dosimeters with high spatial resolution and tunable responsive range from 0 up to 225 kGy were demonstrated based on the decrease of lattice distance caused by chain scission or crosslinking of polymer networks. Compared with the conventional radiochromic dosimeters, this design possesses more flexibility in composition or microstructure and exceptional pre-irradiation stability against light and temperature. In addition, their uniqueness leads to convenient device-free readout techniques through naked-eye color-strip calibration and cell phone-based measurement using hue value detection. In conclusion, our work presents the necessary dosimeters for more direct and effective dose verification in industrial and medical applications.

PET-RAFT Increases Uniformity in Polymer Networks.

Photoinduced electron/energy transfer (PET)-reversible addition-fragmentation chain transfer polymerization (RAFT) and conventional photoinitiated RAFT were used to synthesize polymer networks. In this study, two different metal catalysts, namely, tris[2-phenylpyridinato-C2,N]iridium(III) (Ir(ppy)3) and zinc tetraphenylporphyrin (ZnTPP), were selected to generate two different catalytic pathways, one with Ir(ppy)3 proceeding through an energy-transfer pathway and one with ZnTPP proceeding through an electron-transfer pathway. These PET-RAFT systems were contrasted against a conventional photoinitated RAFT process. Mechanically robust materials were generated. Using bulk swelling ratios and degradable cross-linkers, the homogeneity of the networks was evaluated. Especially at high primary chain length and cross-link density, the PET-RAFT systems generated more uniform networks than those made by conventional RAFT, with the electron transfer-based ZnTPP giving superior results to those of Ir(ppy)3. The ability to deactivate radicals either by RAFT exchange or reversible coupling in PET RAFT was proposed as the mechanism that gave better control in PET-RAFT systems.

Unbreakable Hydrogels with Self-Recoverable 10 200% Stretchability.

Design of tough hydrogels maintaining structural integrity under multivariable mechanical loads remains hugely challenging because the anticipated characteristics such as stretchability, strength, toughness, and fracture resistance can hardly be compatible. Herein, a simple but robust hydrogel network formed by copolymerization of divinyl benzene with acrylamide in micellar solutions for ultra-high fracture resistance and self-recoverable stretchability is proposed. The network provides dynamic association of hydrophobic domains and homogeneous crosslinking of hydrophilic chains, which shows step-by-step deformation process. The dynamic associations allow recoverable small deformations, then the homogeneous crosslinking ensures reversible unfolding and alignment of polymer chains to self-strengthen for ultra-large deformations without crack propagations. The resultant hydrogels exhibit comprehensive unbreakable feature with self-recoverable ultra-high stretchability (100% recovery from 10 200% strain), superior fracture resistance (toughness > 26kJ m-2 ), and anticrack propagation and fatigue (fatigue threshold: ≈2.5kJ m-2 ). Even the prenotched hydrogels can undergo tens cyclic loads at 10 200% strain and thousands cyclic loads at 200% strain without noticeable changes in mechanical performance. The robust network prepared from homogeneous hydrophobic crosslinking provides a facile approach and a new mechanism to explore tough hydrogels with superior antifracture and extreme self-recoverable deformability for diverse applications.

Empirical investigations on the effects of ionizing radiation on epoxy structural adhesives and resins: An overview

Depending on the type of application, ageing effects can highly influence the properties of adhesives. Radiation environment as it can be found in space missions, nuclear reactors – both fusion and fission and particle detectors represents hazardous conditions for adhesives due to the polymer chains of which it is composed. Ionizing radiation interacts through the mechanism of chain scission and crosslinking with these chains resulting in a change of physical properties. In the present study, a comprehensive literature review is conducted regarding the influence of ionizing radiation on the mechanical properties of epoxy adhesives. Radiation damage tests are expensive and complex in terms of operational safety. Therefore, it is desirable to screen the results of previously conducted experiments. 126 data sets collected from about 46 articles are analysed, homogenised, and visualised to provide an overview of the current state of this field of research. The data is categorised according to the performed test and the type of applied load. Mechanical properties are plotted over irradiation dose. Since conducting irradiation tests are often costly and includes hazards, the collection of data sets presented in this study brings huge benefit to the adhesive community. In the future, high demand for such data is becoming apparent due to the recent boom in the space industry and the major efforts made in the field of nuclear fusion development. The provided data can be used by designers, engineers, and scientists for sizing adhesives joints under radiation environment by taking this particular ageing effect into account.

Gravimetric analysis of stability of polymeric materials during exposure to chemical disinfectants at different temperatures

The goal of this study was to evaluate the impact of thermal and chemical aging processes on high-density polyethylene (HDPE), low-density polyethylene (LDPE), unplasticized polyvinyl chloride (U-PVC), and high-impact polyvinyl chloride (Hi-PVC) pipes. The materials were exposed to 1-10ppm chemical disinfectants [chlorine dioxide (ClO2) and hypochlorite (HOCl)] at 40-80°C for 1200h. The diffusion properties of the materials were systematically analyzed based on the change in their sorption characteristics and activation energies according to the Arrhenius model. Moreover, the structural changes were analyzed with scanning electron microscopy (SEM), Fourier transform infrared (FTIR) radiation, and thermogravimetric analysis (TGA). The results show that the materials have Fickian characteristics in the aging environment. Specifically, the water sorption rates of HDPE and LDPE increase first and then decrease after reaching saturation (Ms); those of U-PVC and Hi-PVC its increasing continuously with different rate. This behavior of materials was prominent for ClO2 at high temperature and disinfectant dose because of polymeric chains crosslinking and rearrangement, extraction of monomers, and stable compounds removal during aging under exposed conditions. The deleterious effects decreased the activation energies of the materials and increased the concentrations of carbonyl groups [CO] via the formation of ketones, aldehydes, and carboxylic acids. The decomposition temperature increased with the changes in the material morphology and elemental contents under the investigated conditions. Moreover, LDPE and Hi-PVC were more severely affected in the thermal aging process with 10mg.L-1 ClO2 at 80°C.

Cellulose-based solid and gel polymer electrolytes with super high ionic conductivity and charge capacity for high performance lithium ion batteries

Polymer electrolytes are one of the most effective alternatives to liquid electrolytes to extend lithium ion batteries (LIBs) safety. However, they suffer from low conductivity and charge capacity. In this work, to overcome these tremendous disadvantages, cellulose acetate (CA) and oxidized carboxymethyl cellulose (OCMC) polymer electrolytes obtained from sugarcane and cotton, respectively, are used as polymer electrolytes in LIBs. Then, the effect of short (citric acid) and long (polyvinyl alcohol (PVA)) chain crosslinker to create polymer networks and solid and gel state of electrolytes on the electrochemical properties are investigated. Gel CA-PVA and solid OCMC-PVA electrolytes indicated the best results. Additionally, each CA and OCMC, in both gel and solid state exhibited ionic conductivity in order of 10−2 S cm−1, charge capacity over 230 mAh g−1, capacity retention of 90% after 100 cycles, excellent electrochemical stability upper than 4.5 V, supreme lithium transfer number (∼ 0.8), and good thermal stability. The electrolytes prepared here bring safe and highly efficient LIBs and are a very serious competitor to liquid electrolytes.

Polyphenol-Incorporated Composite Nanogels of Multimodal Interactions for Enhanced Gel Stability and Cisplatin Delivery

Naturally abundant polyphenols that can readily undergo the facile cross-linking of polymer chains have been of great interest for functional hydrogel formation and its potential biomedical applications. Herein, we report that the internal incorporation of tannic acid (TA) as a natural polyphenol additive at the chitosan-based nanogel templates can enhance the self-association of physically cross-linked polymer networks upon dilution, as well as the colloidal gel stability in protein solution. This is driven by the multivalent hydrogen bonding and π-stacking capability of TA, as verified by the viscosity estimation of diluted nanogel solution, coupled to the conformation-dependent excimer emission of stacked fluorophores in polymer networks, which also allows for the Stern-Volmer analysis of the TA-induced quenching property. Furthermore, the excellent coordination generality of TA for versatile metallic cations enables the facile immobilization of a cisplatin pharmacophore inside the nanogels for acid-sensitive drug release and the potential delivery of metallic components.

Topology of multiple cross-linked Su-Schrieffer-Heeger chains

In polymer science, cross-linking of polymer chains yields a substantially modified system compared with the one-dimensional (1D) constituent chains, due to the increase of dimensionality and effective seeding by defects (cross-linking sites). Inspired by this concept, we analyze topological features of a unit cell of a generalized topological mesh comprised of several 1D Su-Schrieffer-Heeger (SSH) lattices cross-linked via a single site. The coupling site functions as a defect with protected states in the trivial regime and induces edges inside the bulk with protected localized states centered around it in the topological regime. When more than two lattices are coupled by the defect, namely, a graph dimensionality larger than one, the crossed chains support two types of localized eigenstates around the defect. One type is highly controllable by modifying the cross-linking strength, enabling broad tuning of eigenenergies from being submerged in the bulk band to becoming highly isolated and protected. We show that these unique features can be explained by an equivalence of the system to an SSH chain coupled nonreciprocally to an external reservoir, yielding a unique pseudospectrum for both the bulk and localized states, with spatially symmetric eigenstates. Applying non-Hermiticity by adding gain and loss to alternating sites, relevant, for example, to a possible realization of topological coupled-laser fabric, we observe an abrupt transition of the topologically protected midgap state from antilocalized to localized near the defect. By changing the gain-loss parameters, we observe a cascaded spatial symmetry breaking of the supported states at exceptional points where parity-time symmetry is broken, for both the localized and the bulk states, exhibiting various phases.