Residual Functional Groups Research Articles

Defect reconstructions in graphene for excellent broadband absorption properties with enhanced bandwidth

A rapid and controlled reduction method of graphene oxide (GO) along with their performances as broadband frequency absorbers is demonstrated in this report. The microwave-controlled rapid GO reduction technique was adopted to control the exfoliation, structural defects, and the localized electron concentrations while keeping the carbon network in graphene intact. The reduction technique is facile and scalable to produce gram-scale graphene with a controlled manner for preparing a sprayable, lightweight coating (coating thickness ~100–120 μm) throughout a large-area (~225 mm diagonal distances) substrate. The as-prepared coating was explored as active broadband frequency absorbing material in the 4–15 GHz frequency region. We obtained extraordinary absorption properties with an absorptivity average ~96% along with the successive broadening of the bandwidth of ~8.5 GHz throughout the absorption band. The retrieved real and imaginary parts of the surface impedance signify proper impedance matching with the free space; thereby providing high absorption at the aforementioned frequency band. The presence of residual oxygen-containing functional groups results in the differential ability to accumulate electrons, which generate the electric dipole under alternating electromagnetic field while electron hysteresis in these dipoles results in additional surface polarization, which effectively increases the microwave absorption potential of rGO compared to pristine GO.

Reactivity of Ca and P precursors to form hydroxyapatite and its influence on the properties of the obtained powders

Synthesis of hydroxyapatite has been profusely studied in the literature due to the similarities between this calcium phosphate and the inorganic component of natural bone. Despite the numerous synthesis methods explored, most of the previous studies are focused on the effect of experimental conditions reducing the importance of the chemical reagents selected as precursors. In this work, four combinations of chemical reagents were used for synthesizing hydroxyapatite powders by a sol-gel method. Conditions for removal of residual functional groups from precursors and its influence on the evolution from amorphous to crystalline powders were studied. Nanocrystalline hydroxyapatite with high thermal stability was obtained by using calcium nitrate or calcium acetate with phosphoric acid or ethyl phosphite as precursors of Ca and P respectively. The use of calcium acetate combined with ethyl phosphite delays the formation of the inorganic network due to retention of acetate groups requiring higher calcining temperatures.

A reduced graphene oxide/bi-MOF-derived carbon composite as high-performance microwave absorber with tunable dielectric properties

In this paper, a reduced graphene oxide/bi-MOF-derived carbon (RGO/bi-MDPC) composite is studied as high-performance microwave absorber with tunable dielectric properties. The dielectric parameter of the RGO/bi-MDPC could be optimized by changing annealing temperature. The optimal sample presents the excellent microwave absorbing performance with the effective absorption bandwidth covering the whole X band with a thickness of 3.4 mm while the minimum reflection coefficient reaches − 33.8 dB at 8.8 GHz with the thickness of 3.7 mm. The specific porous structure, residual oxygen functional groups, and abundant interface contribute to enhanced microwave absorption performance. This work indicates that the bi-MOF-derived porous carbon could be used as nanostructured phase to improve the microwave absorptive capacity of RGO composites.

Citrate‐Based Tannin‐Bridged Bone Composites for Lumbar Fusion

AbstractConventional bone composites consistently fail to mimic the chemical composition and integrated organic/inorganic structure of natural bone, lacking sufficient mechanics as well as inherent osteoconductivity and osteoinductivity. Through a facile surface coating process, the strong adhesive, tannic acid (TA), is adhered to the surface of the natural bone component, hydroxyapatite (HA), with and without the immobilization of in situ formed silver nanoparticles. Residual functional groups available on the immobilized TA substituents are subsequently covalently linked to the citrate‐based biodegradable polymer, poly(octamethylene citrate) (POC), effectively bridging the organic and inorganic phases. Due to the synergistic effects of the tannin and citrate components, the obtained citrate‐based tannin‐bridged bone composites (CTBCs) exhibit vastly improved compression strengths up to 323.0 ± 21.3 MPa compared to 229.9 ± 15.6 MPa for POC‐HA, and possess tunable degradation profiles, enhanced biomineralization performance, favorable biocompatibility, increased cell adhesion and proliferation, as well as considerable antimicrobial activity. In vivo study of porous CTBCs using a lumbar fusion model further confirms CTBCs' osteoconductivity and osteoinductivity, promoting bone regeneration. CTBCs possess great potential for bone regeneration applications while the immobilized TA additionally preserves surface bioconjugation sites to further tailor the bioactivity of CTBCs.

Electrochemical studies of NADH oxidation on chemically reduced graphene oxide nanosheets modified glassy carbon electrode

In this study, the electrochemical oxidation of NADH was investigated on chemically reduced graphene oxide (CRGO) modified glassy carbon electrode (GCE) using various electrochemical techniques. CRGO was prepared by modified Hummer's method and characterized using transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and UV–vis spectroscopy respectively. The TEM studies revealed the presence of nanosheets and the incorporation of residual functional group was confirmed through FTIR spectroscopy. Raman analysis showed the corresponding D and G band with a blue shift for CRGO nanosheets. Also the CRGO showed high defect compared to GO as elucidated from ID/IG ratio. The initial electrochemical studies were carried out using cyclic voltammetry wherein the CRGO/GCE exhibited low overpotential and high oxidation current compared to GO/GCE and bare GCE. Kinetic studies revealed that the oxidation is an adsorption controlled reaction and the number of electron transfer was determined using hydrodynamic voltammetry. Further, the EIS analysis was carried out at various potentials to study the charge transfer kinetics at the electrode/electrolyte interface. As the applied potential is varied from the double layer to Faradaic region, the charge transfer resistance decreases which indicates the NADH oxidation at the corresponding potential. Also, the decrease in the double layer capacitance confirms the adsorption of reaction products leading to fouling of the electrode surface. The detection of NADH on CRGO/GCE was performed using differential pulse voltammetry (DPV). The limit of detection was found to be 21.85 μM with a linear range of 50 μM–650 μM. It is found that CRGO showed better activity compared to GO but their electron transfer kinetics is very poor and suffered from electrode fouling.

The reaction of oxidorhenium(v) with dipodal and tripodal aroylhydrazines: formation of dinuclear and trinuclear aroylhydrazone-bridged rhenium(v) complexes

The chemistry of aroylhydrazines has been attracting attention mainly due to the residual functional group, –CONH–NH2, which has important effects on hydrophilicity and has the potential to provide special interaction sites for targeting molecules.

A retrospective study of the relationship between postoperative urine output and one year transplanted kidney function

BackgroundKidney transplantation (KT) is the most obvious method of treating a patient with end-stage renal disease. In the early stages of KT, urine production is considered a marker of successful reperfusion of the kidney after anastomosis. However, there is no clear conclusion about the relationship between initial urine output after KT and 1-year renal function. Thus, we investigated the factors that affect 1-year kidney function after KT, including urine output.MethodsThis retrospective study investigated the relationship between urine output in the 3 days after KT and transplanted kidney prognosis after 1-year. In total, 291 patients (129 living-donor and 162 deceased-donor transplant recipients) were analyzed; 24-h urine volume per body weight (in kilograms) was measured for 3 days postoperatively. The estimated glomerular filtration rate (eGFR), determined by the Modification of Diet in Renal Disease algorithm, was used as an index of renal function. Patients were grouped according to eGFR at 1-year after KT: a good residual function group, eGFR ≥60, and a poor residual function group, eGFR < 60.ResultRecipients’ factors affecting 1-year eGFR include height (P = 0.03), weight (P = 0.00), and body mass index (P = 0.00). Donor factors affecting 1-year eGFR include age (P = 0.00) and number of human leukocyte antigen (HLA) mismatches (P = 0.00). The urine output for 3 days after KT (postoperative day 1; 2 and 3) was associated with 1-year eGFR in deceased-donor (P = 0.00; P = 0.00 and P = 0.01). And, postoperative urine output was associated with the occurrence of delayed graft function (area under curve (AUC) = 0.913; AUC = 0.984 and AUC = 0.944).ConclusionAlthough postoperative urine output alone is not enough to predict 1-year GFR, the incidence of delayed graft function can be predicted. Also, the appropriate urine output after KT may differ depending on the type of the transplanted kidney.Trial registrationClinical Research Information Service of the Korea National Institute of Health in the Republic of Korea (KCT0003571).

Unveiling the Working Mechanism of Graphene Bubble Film/Silicon Composite Anodes in Li-Ion Batteries: From Experiment to Modeling

In spite of the fact that there are plenty of recent studies on Si/graphene composite anodes, the influence of graphene on Li diffusion at the interface and lithiation associated mechanical behavior have not been well-understood. Furthermore, it is still a technical challenge to maintain a high capacity and an ultralong cycle life with high mass loading. Using a simple self-assembly approach, we have developed an all-integrated architecture of Si nanoparticles (SiNPs) encapsulated inside reduced graphene oxide (rGO) bubble films anchored in a 3D rGO macroporous network (encapsulated Si@rGO) as an anode for Li-ion batteries (LIBs). The enhanced electrochemical performance and structural stability of the anode are accomplished by the unique multifunctional rGO bubble film, which smoothly wraps SiNPs with notable void spaces. Its residual functional groups covalently bind with SiNPs, preventing their detachment from the electrode. The bubble wrap together with the outermost 3D framework accommodate the volume change, contributing to a stabilized solid electrolyte interphase (SEI) layer while maintaining ionic and electronic conductive pathways. Density functional theory (DFT) simulations show that the graphene coating boosts the mobility of the Li atoms at the Si-graphene interface. Molecular dynamics (MD) simulations confirm that graphene bubble film can effectively control the stress build-up near the Si surface, maintaining the structural integrity of the anode. The encapsulated Si@rGO anode with a mass loading of 2.6 mg cm -2 demonstrates exceptional cycling stability and superior rate capabilities. The anode demonstrates a high reversible capacity of 1346 mAh g -1 after 200 cycles at 500 mA g -1. Even at a high current density of 2.5 A g -1, a reversible capacity of 998 mAh g -1 is maintained after 1000 cycles with a capacity retention of 97%.

Comparative study of deoxygenation behavior for graphene oxide with different oxidation degree and mildly reduced graphene oxide via solid-state microwave irradiation

The influence of the oxidation degree of graphene oxide (GO) on its deoxygenation efficiency via hybrid microwave heating (HWH) method by using graphite powder as the external susceptor was investigated, and the response behavior was compared with the situation when GO is directly submitted to microwave irradiation. In addition, the deoxygenation behavior of mildly reduced GO (VRGO) that was obtained via chemical reduction by Vitamin C was compared with that of GO during above two microwave heating processes. No response of GO to microwave irradiation when GO samples are exposed directly to microwave, no matter how the oxidation degree is. However, the VRGO sample can be heated when it is solely submitted to microwave irradiation. The partial reduction of GO leads to enhancement of the dielectric parameters, and the residual defects and oxygen-containing functional groups not only can improve the impedance matching characteristics, but also produce defects polarization relaxation and dipole polarization relaxation, which are all beneficial to the microwave penetration and absorption. The deoxygenation efficiency of VRGO is lower in comparison with GO under the HWH condition, which should be attributed to higher amount of epoxides in GO samples that can be easily reduced in a mixed heating mode.

Semi-simultaneous Saccharification and Fermentation of Ethanol Production from Sargassum horneri and Biosorbent Production from Fermentation Residues

One of the fundamental goals of bio-ethanol production is to find the alternative of traditional land-relied feedstock. A kind of macroalgae, Sargassum horneri (S. horneri) was chosen as the bio-source for ethanol production in the present investigation. The bioethanol was achieved by acid-pretreated, hydrolysis, and semi-simultaneous saccharification and fermentation (S-SSF) at small pilot scale. Immobilization of Pichia stipites in calcium alginate was adapted in the S-SSF process. Furthermore, effects of pre-hydrolysis time, cellulase loading, fermentation temperature and fermentation time on the concentration, and yield of bio-ethanol were evaluated by using response surface methodology (RSM). A maximum bioethanol concentration (2.89 g/L), and maximum bioethanol yield (0.11 g/g raw material) at cellulase loading (10 IU/g raw material), pre-hydrolysis time (53 min), SSF temperature (32 °C) and SSF time (14 h) were observed. The optimized bioethanol production data series fit the Gompertz model and modified Logistic model with an R2 value of 0.997. The obtained Gompertz and modified Logistic coefficients indicated that S. horneri can serve as an efficient substrate for bioethanol production. The fermentation residues were used for typical dyeing contamination adsorption, the existence of the residual lignin and exposure functional groups made it an effective adsorbent, which followed the pseudo-second-order kinetics. These results are helpful for the scale-up development of lignocellulosic macroalgae based bioethanol production and fermentation residue use.

Thermoresponsive in Situ Forming Hydrogel with Sol-Gel Irreversibility for Effective Methicillin-Resistant Staphylococcus aureus Infected Wound Healing.

An in situ forming hydrogel has emerged as a promising wound dressing recently. As physically cross-linked hydrogels are normally unstable, most in situ forming hydrogels are chemically cross-linked. However, big concerns have remained regarding the slow gelation and the potential toxicity of residual functional groups from cross-linkers or the polymer matrix. Herein, we report a sprayable in situ forming hydrogel composed of poly(N-isopropylacrylamide166-co-n-butyl acrylate9)-poly(ethylene glycol)-poly(N-isopropylacrylamide166-co-n-butyl acrylate9) copolymer (P(NIPAM166-co-nBA9)-PEG-P(NIPAM166-co-nBA9),denoted asPEP) and silver-nanoparticles-decorated reduced graphene oxide nanosheets (Ag@rGO, denoted asAG) in response to skin temperature. This thermoresponsive hydrogel exhibits intriguing sol-gel irreversibility at low temperatures for the stable dressing of a wound, which is attributed to the inorganic/polymeric dual network and abundant coordination interactions between Ag@rGO nanosheets and PNIPAM. The biocompatibility and antibacterial ability against methicillin-resistant Staphylococcus aureus (MRSA) of this PEP-AG hydrogel wound dressing are confirmed in vitro and in vivo, which could transparently promote the healing of a MRSA-infected skin defect.

Origin of Charge Trapping in TiO2/Reduced Graphene Oxide Photocatalytic Composites: Insights from Theory.

Composites of titanium dioxide (TiO2) and reduced graphene oxide (RGO) have proven to be much more effective photocatalysts than TiO2 alone. However, little attention has been paid so far to the chemical structure of TiO2/RGO interfaces and to the role that the unavoidable residual oxygen functional groups of RGO play in the photocatalytic mechanism. In this work, we develop models of TiO2 rutile (110)/RGO interfaces by including a variety of oxygen functional groups known to be present in RGO. Using hybrid density functional theory calculations, we demonstrate that the presence of oxygen functional groups and the formation of interfacial cross-links (Ti–O–C covalent bonds and strong hydrogen bonds between TiO2 and RGO) have a major effect on the electronic properties of RGO and RGO-based composites. The electronic structure changes from semimetallic to semiconducting with an indirect band gap, with the lowest unoccupied band positioned below the TiO2 conduction band and largely localized on RGO oxygen and carbon orbitals, with some contributions of RGO-bonded Ti atoms. We suggest that this RGO-based lowest unoccupied band acts as a photoelectron trap and the indirect nature of the band gap hinders electron–hole recombination. These results can explain the experimentally observed extended lifetimes of photoexcited charge carriers in TiO2/RGO composites and the enhancement of photocatalytic efficiency of these composites.

Новые метилфенилсилоксановые смолы на основе алкоксисиланов

Currently interested in the reaction for producing oligosilsesquioxanes based on acidolysis alkoxysilanes. In this regard, the author was given the following tasks: development of optimal synthesis conditions; preparation of new methylphenylsiloxane resins with different properties. In this paper, the properties of new methylphenylsiloxane resins (MPR) with various radicals in silicon were studied. New IFSS were obtained by a new universal technology-acidolysis of a mixture of methyltriethoxysilane (MTEOS) and phenyltriethoxysilane (PTEOS) with various radicals, which are environmentally friendly raw materials. The obtained MPR were characterized by NMR spectroscopy on 1H and 29Si nuclei. Spectra were recorded at room temperature in deuteroacetone using Bruker AM-360 Fourier spectrometer. 29Si NMR spectra were measured using the pulse program "Inverse Gated Heteronuclear Decoupling". The content of residual functional groups (Si-OH, Si-OEt) in IFSS was determined by functional analysis methods. Determination of ethoxy groups and hydroxy groups was carried out by iodometric and aluminohydride method, respectively. Thermogravimetric analysis was performed on the device Derivatograph-H (firm Mom). TGA studies were carried out in the argon atmosphere and in the air at a heating rate of 10 ºC/min. Measurements of kinematic viscosity of 20 % and 50% by weight. toluene solutions of MPR were carried out at 20 °C on the viscometer HPV-2. The reaction acidolysis of methyltriethoxysilane and oligophenylenes is a convenient and versatile method for the synthesis of new heat-resistant resins methylphenylsiloxanes. In the course of the study, it was found that the resins obtained on the basis of organoalkoxysilanes are characterized by higher thermal and thermo-oxidative stability.

A comparative investigation of aminosilane/ethylene diamine–functionalized graphene epoxy nanocomposites with commercial and chemically reduced graphene: static and dynamic mechanical properties

Incorporation of nanosized fillers into polymers has created new composites by expanding the functions and applications while retaining the excellent engineering and processing flexibility inherent to polymers. Compared with traditional nanofillers, more recently, graphene has been increasingly preferred as a candidate for strengthening and/or functionalizing polymer nanocomposites. The easy synthetic methods, low cost, and non-toxicity of graphene make this material attractive for many technological applications. Herein, we discuss the synthesis of different types of graphene from graphite via graphene oxide reduction. Commercial graphene (CG) as well as the synthesized chemically reduced graphene (CRG) and chemically reduced silane-modified graphene (SMG) were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and ultraviolet visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. The results confirmed that the silane molecules were attached on the surface of graphene sheets. Simultaneously, most of residual oxygen-containing functional groups of GO were reduced and the sp2-hybridized structure of graphene was restored. The utilization of these graphene-based materials in the fabrication of epoxy nanocomposites with enhanced properties has been explored and compared with those of neat epoxy and CG/epoxy nanocomposites. Inclusion of 0.25 phr CRG and SMG in an epoxy resin showed 28% and 32% increases in tensile strength, and the corresponding fracture toughness displayed 67.6% and 66.3% increase respectively. The improved mechanical properties of SMG/epoxy nanocomposites might be due to the uniform dispersion of functionalized graphene and strong interfacial bonding between modified graphene and epoxy resin.

Enhanced lithium storage performance of graphene nanoribbons doped with high content of nitrogen atoms

Nitrogen doping can provide a large number of active sites for lithium-ion storage, thus can yield a higher capacity for lithium-ion batteries. However, most of the reported N-doped graphene-based materials have low nitrogen content (<10 wt%) as the introduction of nitrogen atoms prefer to be produced at edges and defects in the graphene lattices. Owing to the formation of edges and defects, the doped states or active sites can easily be located and nitrogen contents can be determined precisely. Here we present the preparation of N-doped graphene nanoribbons with high nitrogen contents (11.8 wt%) and a facile tunable configuration of doped states. The material can be used as an anode for lithium-ion batteries and shows a higher capacity (the electrode has a reversible capacity of 1100.34 mA h g−1 at a charge/discharge rate of 100 mA g−1, corresponds to a discharge time of about 9 h), better rate performance (the electrode has a reversible capacity of 471 mA h g−1 at the current density of 2 A g−1, corresponds to a discharge time of about 11.6 min) and improved cycling stability (87.37% of the initial capacity after 200 cycles). The experimental results and first-principle calculations suggest that the residual oxygen-containing functional groups of N-doped graphene nanoribbons promote the formation of pyrrolic nitrogen at edges and substantially increase the room for nitrogen doping. This work opens new strategies for designing and developing N-doped graphene anodes for high performance lithium-ion batteries.

Synthesis and characterization of graphene oxide capped sulfur/polyacrylonitrile composite cathode by simple heat treatment

ABSTRACTA Sulfur/Poly (acrylonitrile) (PAN)/Graphene oxide (GO) hybrid electrode with inter connected structure is prepared through a simple heat treatment. In this process, the formation of a unified poly acrylonitrile /graphene oxide conductive network is accompanied by the uniform loading of sulfur, with a fraction of 52%. The as-prepared S/PAN/GO hybrid delivers an initial capacity of 1424 mAhg−1 at 0.1C. The electrochemical performance of the composite is ascribed to the conductive network designed by interconnected GO and PAN, which supply an unimpeded and uninterrupted path for electron and Li-ion transfer and accommodate the volume variation of sulfur during charge/discharge cycling. Furthermore, the residual functional groups on S/PAN/GO composite can support close contact of the conducting matrix with sulfur and efficiently confine the diffusion of polysulfides. This study gives a green and highly active technique for carbon–sulfur electrode construction for lithium–sulfur batteries. The electrochemical execution improvement can be attributed to the multiple effects of the PAN and GO additive such as conductivity, sulfur distribution, and an active absorber for the reaction products.

Comparative Study of EPR and Optical Properties of CdS, TiO2 and CdS-TiO2 Nanocomposite

An economical chemical route is used to synthesize a titanium oxide-based nanocomposite (NC) which has properties that may help to develop photocatalysts with improved efficiency in the visible region of solar light. Investigation of opto-electronic properties has been carried out for a CdS, TiO2 and CdS-TiO2 NC at room temperature. Structural properties of the CdS and TiO2 nanoparticles and the CdS-TiO2 NC were investigated using x-ray diffraction and transmission electron microscopy techniques. How incorporation of CdS nanoparticles affects the structural properties of pure TiO2 was also studied. Change in optical behavior was compared using UV–visible and photoluminescence spectra, and the presence of residual functional groups were indicated by Fourier-transform infrared analysis of the samples. The measurement of band levels was carried out by cyclic voltammetry (CV) and the band gap estimated from UV–visible was compared to that obtained by CV. The electron paramagnetic resonance technique was used for the investigation of the electronic properties of the samples.

Patients with cystic fibrosis having a residual function mutation: Data from the Italian registry.

CFTR mutations permitting residual function (RF) of the CFTR protein are disease-causing. These mutations are associated with a pneumopathy that is delayed in onset and is slower in progression than are more common forms of cystic fibrosis (CF), although the disease may become severe in some patients. RF mutations are among the most frequent in Italy, thus encouraging investigation of their prevalence and associated phenotypes. Data from the Italian Registry were used to compare patients with at least one RF mutation with those homozygous for F508del. A total of 806 patients bearing at least one RF mutation were identified among 5204 registered patients (15.5%). The RF patients were older than the F508del homozygotes (median age 26.0 years vs 19.8 years, respectively), with a higher median age at diagnosis (6.3 years vs 0.2 years, respectively) and a lower median sweat chloride value (76.0 mmol/L vs 100.0 mmol/L, respectively). In the RF group, lung infections and comorbidities were less prevalent than those in the F508del homozygotes, while better FEV1 and nutritional status were observed at all ages. Within the RF group, RF/F508del subjects showed more severe pneumopathy than did patients with RF/other mutations. In particular, the 3849 + 10kbC → T/F508del subjects had worse FEV1 and a higher prevalence of lung infections than did patients with other genotypes. Patients with RF mutations are numerous in Italy and have a milder disease phenotype than do F508del homozygotes. Inside the RF group, F508del heterozygotes and, in particular, 3849 + 10kbC → T/F508del patients showed more severe pneumopathy.

Improve the Performance of Soy Protein-Based Adhesives by a Polyurethane Elastomer.

The purpose of this study was to improve the performance of soy protein isolate (SPI) adhesives using a polyurethane elastomer. Triglycidylamine (TGA), SPI, thermoplastic polyurethane elastomer (TPU), and γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH-560) were used to develop a novel SPI-based adhesive. The residual rate, functional groups, thermal stability, and fracture surface micrographs of the cured adhesives were characterized. Three-ply plywood was fabricated, and the dry/wet shear strength was determined. The experimental results suggested that introducing 2% TGA improved the residual rate of the SPI/TGA adhesive by 4.1% because of the chemical cross-linking reaction between epoxy groups and protein molecules. Incorporating 7% TPU into the SPI/TGA adhesive, the residual rate of the adhesive increased by 5.2% and the dry/wet shear strength of plywood bonded by SPI/TGA/TPU adhesive increased by 10.7%/67.7%, respectively, compared with that of SPI/TGA adhesive. When using KH-560 and TPU together, the residual rate of the adhesive improved by 0.9% compared with that of SPI/TGA/TPU adhesive. The dry and wet shear strength of the plywood bonded by the SPI/TGA/TPU/KG-560 adhesive further increased by 23.2% and 23.6% respectively when compared with that of SPI/TGA/TPU adhesive. TPU physically combined with the SPI/TGA adhesive to form a interpenetration network and KH-560 acted as a bridge to connect TPU and SPI/TGA to form a joined crosslinking network, which improved the thermo stability/toughness of the adhesive and created a uniform ductile fracture section of the adhesive.

The sequenced structure of amino-alcohol-based random poly(ester amide)s

Random amino-alcohol-based poly(ester amide)s were synthesized using adipic acid and differently substituted amino-alcohols, namely 2-amino-ethan-1-ol, 1-amino-propan-2-ol, 2-amino-butan-1-ol and 2-amino-2-methyl-propan-1-ol. The effect of substitution on the yield and fine structure was investigated using residual functional group analysis, SEC and NMR. The functional group analysis and SEC proved the blocking effect of small substituents on direct polycondensation. The NMR data suggested a sequenced structure that could cause the formation of different crystalline phases in linear amino-alcohol-based poly(ester amide)s. Three different crystalline phases with different thermal stability and crystallization rate were observed with DSC and WAXS. The crystalline nature of the poly(ester amide)s proves the sequenced organization along the backbone.