Flame retardant thermoplastic polyurethane elastomer (TPU) applied in the field of wires and cables often need a large amount of flame retardant additive. To improve the efficiency, this work prepared a highly effective novel phosphorus-containing Schiff base derivative flame retardant N, N′-bis[1-(salicylidene) methanephenylphosphonic acid]-1,2- ethylene diamine (SMAE), which was successfully synthesized via the addition reaction between Phenylphosphinic acid and N, N'-bis(salicylidene)ethylenediamine. It had great thermal stability (T5%, 271 ℃) and char forming ability (29.6 wt. % at 700 °C), which was added to TPU at different additions to improve the flame retardant performance. Results showed that only 4% SMAE increased the limiting oxygen index value of TPU from 22.3% to 32%, passing UL 94 V-0 rating. Meanwhile, the peak heat release rate, average heat release rate and total heat release of TPU also decreased by 3%, 19% and 16%, respectively. The constituent and microscopic morphology of the residual char of TPU samples were observed by Fourier transform infrared spectroscopy and scanning electron microscopy, which indicated SMAE produced phosphinic acid to promote the formation of a more complete and dense char layer for TPU. The pyrolysis gas phase products were recorded by thermogravimetric Fourier transform infrared spectroscopy. The results showed that SMAE could produced PO∙ terminated the chain reaction and released inert gases (carbon dioxide and ammonia) to dilute combustible gases during combustion. Therefore, SMAE can endow TPU with excellent flame retardancy.

In recently years, polyol prepared from biobased renewable resources has attracted researchers' attention to synthesize green environmental polyurethane. Among numerous polyols, poly (trimethylene ether glycol) (PO3G) is used to prepare polyurethane due to outstanding performances. This paper aims to prepare photosensitive polyurethane acrylate based on 100% renewable PO3G with low viscosity, great flexibility and fast curing speed. The physical and thermal properties of materials were characterized by FTIR, ATR, DSC and DMA. The mechanical properties were measured emphatically. All the results suggest the prepared PO3G-based resins exhibit excellent strength and flexibility with low viscosity. On the other hand, the blocking agent with dynamic covalent bond was introduced to ensure the low viscosity of resins under UV curing. With the break of blocking agent, the isocyanate group could be fully released and carry out chain extension with amine during secondary curing to form polyurethane network and comprehensive performance of resins. Furthermore, the prepared materials have significant advantage and show good application potential in UV-curing 3D printing.

SiO2 microspheres (N98) is a kind of spherical silica with a microstructure of 200 ~ 400 nm. In this work, different silane coupling agents were used for modification of N98 through wet mixing process. 3-(Trimethoxysilyl)propyl methacrylate (KH570) was the modification agent for modifying N98 through the comprehensive analysis of the curing property, Mooney viscosity, hardness, tensile strength, tear strength and fatigue properties of NR/N98 composites. The proportion of KH570 to N98 was further optimized and its modification effect was analyzed by FTIR and SEM. The effects of untreated N98 and KH570 treated N98 (N98@KH570) on the fatigue resistance of NR were mainly studied, and the effects on the basic properties of NR/N98 composites were comprehensively studied. The results show that N98@KH570 powder has no effect on the curing property, tensile property and wear resistance of NR/N98 composites, but can increase the viscosity of Mooney, reduce the tear strength, and slightly increase the hardness of NR/N98 composites. Nevertheless, N98@KH570 is compounded with NR, and the fatigue property of NR is improved. However, the fatigue property of NR can be significantly reduced by NR compounded with untreated N98. The fatigue resistance of NR is gradually improved with the proportion increase of KH570 to N98. The mass ratio of N98 to KH570 is 10:1 and loading of N98@KH570 is 8 phr, the fatigue resistance of NR is improved 71.4% compared with that of the untreated NR/N98 compounds.

Non-traditional polyesters from low molecular weight Poly (ethylene glycol) (PEG, Mn 4000) and biocompatible Trimesic acid (TMA) were synthesised through stoichiometric feeding of PEG and TMA in the mole ratios starting from 1:0.5 to 1:5. The melt condensation was carried out under catalytic condition for a limited period of 6 h to prohibit gelation of the entire mass due to over-abundance of the functional groups. The polyesters were formed with substantial soluble yield; at lower acid concentration in the feed e.g. 1:0.5, 1:1 and 1:2-they were mostly branched while at higher concentration e.g. 1:3 and 1:5-they were significantly crosslinked. Nearly all the specimens contained partially reacted TMA molecules in the branch ends which made them pH responsive (the hydrodynamic sizes altered with change in pH). The polymers were characterized using solubility, spectroscopy, viscometry and particle size measurements to establish the microstructure, formation kinetics and branched topology. Nuclear magnetic resonance (1H NMR) established the maximum extent of branching (65%) at 1:5 mol composition. Suitability for bioapplication of the polyesters was examined from surface texture study and cell cytotoxicity analysis. The scanning electron microscopic (SEM) images portrayed adequate micro voids on the surface, on the other hand, the cytotoxicity study depicted those surfaces could adhere and support the growth of mammalian cells and also successfully survive the MTT assay.

Abstract This paper explores the effect of nanoclay for improving the interfacial properties of starch bioplastic material filled with cellulose-nanoparticles (CNPs). The CNPs were prepared through acid-hydrolysis process by using acid concentration to break the amorphous region of chopped fiber to produce nano-cellulose. Various CNPs concentration (0.5 – 2.5 wt.%) were dispersed in cornstarch biopolymer matrix to form bioplastic films through solution casting method and listed for thermal and mechanical properties. Cornstarch bioplastic filled with 1.5 wt.% of CNPs showed optimum improvement in thermal and mechanical properties. Furthermore, nanoclay (NC) of varying weight percentage (0.1 – 0.5 wt. %) were added to the optimum improved 1.5 wt.% CNPs filled cornstarch bioplastic material. Hence, the hybrid cellulose-nanoparticles/nanoclay (CNPs/NC) filled cornstarch was improved both thermally and mechanically. The stiffness parameter ( \({\beta }_{f}\) ) and confinement region ( \(C\) ) of the bioplastic during relaxation stage were 0.70 and 1.03 respectively for hybrid fillers at 1.5/0.3_CNPs/NC, which is an indication that nanoclay had a very good reinforcing effect on the starch polymer system. Improved tensile modulus and tensile strength of the CNPs/NC by 639% and 97% respectively were found when compared to CNPs filled cornstarch bioplastic material. Furthermore, the addition of nanoclay slow down the effect of water absorption rate. Hence, the water uptake of the bioplastic film was normalized.

Epoxy resin-based composites have an important and extensive application value in both military and civilian, but their poor fire safety hinders their further development. Therefore, it is very important to improve the flame retardant properties of epoxy resin matrix composites, and a large number of literature reports have appeared in recent years. Biogenic epoxy resin flame retardants have emerged as the times require due to the problems of large amount of addition, difficult dispersion and low interfacial strength of epoxy resin flame retardants, as well as the continuous improvement of people's awareness of green chemistry and sustainable development. In this review, scholars will realize the necessity of flame retardant epoxy resin, understand the burning process, type of flame retardants and flame retardant mechanism of epoxy resin. Mastering the preparation method of epoxy resin flame retardants related to the two most popular biogenic materials, phytic acid (PA) and chitosan (CS), and the influence on the performance of epoxy resin matrix and the flame retardant mechanism. Discovering the advantages, challenges and prospects of biogenic materials PA and CS in the research of flame retardant properties of epoxy resins.

Ferroelectric films have been widely studied for their energy harvesting applications and flexible ferroelectric films for their piezoelectric energy harvesting. In this work, we explore tuning the PVDF/BaTiO3 composite flexible films for pyroelectric energy conversion applications. This work reports the influence of barium titanate particles (BaTiO3) in the formation of β-phase polyvinylidene fluoride (PVDF) on PVDF/BaTiO3 composite films based on Fourier transform infrared and Raman spectroscopic studies. PVDF/BaTiO3 composite films with different weight percentages of BaTiO3 were prepared by spin coating technique. Fourier transform infrared spectroscopy and Raman spectroscopic analysis of PVDF/BaTiO3 composite films indicated that the polar β-phase of PVDF nucleated by the incorporation of BaTiO3 through CF2 interaction with BaTiO3 particles as inferred from the filler percentage dependence study of vibration modes. The 15 wt% concentration of PVDF with 5 wt% of BaTiO3 composite film has higher β-phase content and better crystallinity. The improved film quality, in turn, enhances the pyroelectric coefficient and pyroelectric energy conversion figure of merit.

The phase behavior of ABCBA linear pentablock terpolymers is investigated by using the 3-dimensional self-consistent field theory. In this study, phase diagrams are constructed and used to discuss how the self-assembled morphologies are influenced by the compositions and the Flory–Huggins interaction parameters (χ) among the three components by decreasing symmetric χN value (segregation strength, where N is the total degree of polymerization) from 80 to 30. In the segregation regime of χN from 80 to 50, the microstructures formed by ABCBA linear pentablock terpolymers according to the compositions of the components are very similar. In particular, diverse complex network structures (e.g. diamond, hexagonally perforated lamellae, Fddd, and gyroid) and binary crystalline phases of cylinders and spheres can be observed. This is mainly due to the fact that the two free ends of the A block in the ABCBA linear copolymer allow the macromolecules to relieve packing frustrations. However, in the intermediate system with symmetric χN < 50, the aggregation of each components becomes weaker so that behavior of the pentablock chains is similar to triblock and diblock chains. Accordingly, the diamond and hexagonally perforated lamellae tend to transfer to gyroid and Fddd observed in linear diblock and triblock cases. Moreover, by altering the composition ratio of A/C and the length of the B block, alternatively arranged A/C spheres resemble ionic and metallic crystals (e.g. NaCl, CsCl, Li3Bi, and Nb3Sn) and alternating A/C cylinders with coordination numbers of A/C (equal to 4/4, 6/3, and 4/2) can be still observed by decreasing symmetric χN to 40 in the intermediate regime.

Cell migration determines the complete development of mammalian tissue and other pathological phenomena. To investigate the effect of chemical stimuli on such behavior, cells are triggered to translate by the concentration gradient of different molecules on 2D substrates in vitro. But to date unfortunately the polymeric scaffolds for cell migration in 3D environment with chemical stimuli have not been proposed and developed yet. Herein, a novel 3D composite scaffold with an internal chemical boundary is fabricated by electrospinning and mask-assisted electrospray so that the deposition of PBG-N3 particles is confined at specific area initially. The chemical boundary is subsequently formed after selective surface modification of the particles via click reaction. Using a fluorescent alkyne, the boundary of modified regions is clearly observed by fluorescence microscope. This innovative bio-material has the potential to serve as a promising scaffold for investigating the effect of chemical stimuli on cell migration and growth in 3D environment and further on to the application in tissue engineering.

Terbutylazine (TER)—simetryn (SIE) molecularly imprinted polymers (TER-SIE-MIPs) were prepared by precipitation polymerization with TER and SIE as double template molecules, acrylic acid (AA) as the functional monomer, and acetonitrile as the porogen. A method of molecularly imprinted solid-phase extraction combined with high performance liquid chromatography (MISPE-HPLC) was developed for the determination of four triazine herbicide residues in tobacco leaves. The optimal functional monomer was firstly selected, then the optimal binding ratio between template and monomer was determined by computer simulation algorithm. The adsorption performance of the MIPs to double template molecules was investigated by adsorption experiments. It was found that the MIPs had two types of affinity sites, and good specific adsorption capacity for TER and SIE and their structural analogs. Then TER-SIE-MIPs was used as a solid phase extraction filler to prepare a TER-SIE-MISPE column for pretreatment of spiked tobacco leaves, and the pretreatment liquid was analyzed by HPLC, and the results showed that TER-SIE-MISPE had better enrichment effect on terbutylazine, simetryn, terbumeton and prometryn. The average recoveries of the four triazine herbicides were between 80.95 and 103.15%, and the relative standard deviations (RSD) were 1.82 ~ 2.57% (n = 3), the method can meet the requirements of simultaneous determination of terbutylazine, simetryn, terbumeton and prometryn triazine herbicide residues in tobacco leaves.

Environmentally friendly crosslinked carboxymethyl cellulose-based hybrid hydrogels (CCMC/OMMT) were prepared from a grafting of 2-acrylamide-2-methylpropane sulfonic acid (AMPS) onto CCMC and reinforced with Organo-Montmorillonite (OMMT) in this study as efficient adsorbents for methylene blue (MB). FTIR, SEM, XRD, EDS, XPS, and TGA techniques have been employed to investigate the composition and shape of the setup hydrogels. The MB adsorption ability of CCMC/OMMT was investigated concerning the initial MB concentration, pH, interaction time, and temperature. The capacity of CCMC/OMMT to adsorb on MB was 490.5 mg/g at 313.15 K and pH 7.0. Furthermore, the adsorption kinetics and isotherm were accurately predicted using the pseudo-second-order dynamic theory and Langmuir isotherm theory. The estimated thermal parameters ΔG0, ΔH0, and ΔS0 suggested that the molecules of MB binding on the CCMC/OMMT were spontaneous and endothermic. The procedures of sorption were facilitated by electrostatic attraction and hydrogen-bonding interaction. Additionally, all manufactured hydrogels were reusable for MB removal. As a result, CCMC/OMMT can be used as environmentally safe, productive, and washable stuff for MB in sewage treatment.

The copolymerization of 1,1,1,3,3,3-hexafluoroisopropylacrylate (HFIPA) and 2,2,3,3,4,4,5,5-octafluoropentyl acrylate (OFPA) with N-vinylpyrrolidone (NVP) in the presence of S,S’-dibenzyl trithiocarbonate (BTC) and polymeric RAFT agents based on fluoroacrylates were investigated. The copolymerization process proceeds in a control mode at any conditions investigated that was confirmed by the first order of reaction by monomer and SEC curves. Reactivity ratios of monomers were determined by the Fineman-Ross and Kelen-Tudos models. Aggregation behavior of copolymers at the air/water interface was studied by the Langmuir film balance technique. The influence of the composition and pH of the subphase on the surface properties of copolymers is considered. With the rise of subphase pH, as well as an increase in the mole fraction of NVP in the copolymer, the pressure of the plateau formation process increases. The morphology of LB films of various compositions was studied by atomic force microscopy. With the elevation in the proportion of NVP, a change in the size of micelles is traced.

A modified Gilch polymerization method, with optimized synthesis procedures were utilized to prepare poly(phenylene vinylene) (PPV) derivatives of differing symmetric alkoxyl substituents. The characterization techniques elemental analysis, FT-IR, NMR and LC–MS were utilized for all structural elucidations. 1H NMR spectra of the symmetric dialkyl PPV polymers gave aliphatic protons in region δ 0.84–4.15 ppm and aromatic protons in region δ 7.15–7.19 ppm. The polymers gave yields 37–69% with number-average degree of polymerization (\(\overline{DP}_{n}\)) of range 39–68 and polydispersity indices (PDI) in range 2.61–3.59. Further, the molecular weights, weight- and z-average \(\overline{M}_{w}\) and \(\overline{M} z\) of the polymers were calculated to be in range 35,150–79,770 and 41,300–91,020, respectively. SEM was utilized to examine surface morphologies and the cross-sections of symmetrical dialkyl PPV polymer films. The HCl-doped films of the symmetrical dialkyl PPV polymers gave electrical conductivities in range 0.1847–0.4585 Scm−1. These conductive polymers gear attraction in electronic industries as active semiconductor materials.

A combination of pullulanase debranching, chloroacetic acid etherification and sodium tripolyphosphate esterification was selected for the modification of waxy corn starch (WCS) to ameliorate its properties and expand its application. The results indicated that phosphate carboxymethyl debranched waxy corn starch (PCDWCS) could be used to remove Zn2+ in simulated waste water, and the removal rate of Zn2+ could reach 72.9% at suitable adsorption conditions. The debranching could lead to a decrease in the swelling capacity of WCS, while the carboxymethylation and esterification could improve the swelling capacity. The crystalline structure of WCS was an A-type, but the crystalline structure of debranched waxy corn starch (DWCS) was a C-type. Moreover, the crystalline structures of carboxymethyl debranched waxy corn starch (CDWCS) and PCDWCS were transformed into an amorphous structure. The carboxymethylation and phosphorylation were chiefly completed on the big particles. The characteristic absorption peaks of carbonyl bonds at 1736.8 cm−1 and P = O bonds at 1301.2 cm−1 confirmed that WCS was successfully etherified and esterified.

In this study, the nanocomposite membranes were electrospun using conventional polymers, including polyvinyl chloride (PVC), thermoplastic polyurethane (TPU) and polycarbonate (PC) at different levels of incorporation of the γ-alumina nanoparticles (1, 3 and 5 wt.%). Morphological investigation using SEM images showed that the diameters of the nanofibers were in the range of 155-491 nm. The energy dispersive spectroscopy (EDS) analysis and FTIR test revealed the presence of the γ-alumina nanoparticles (NPs) and characteristic chemical groups in electrospun nanocomposite membranes (ENCMs). The contact angle test showed that the hydrophilic features of the membranes improved with the incorporation of γ-alumina NPs with the decrease of contact angle from 80° to 27°. Mechanical tests exhibited a drop in tensile strength and strain of the nanocomposite membranes by adding more γ-alumina NPs to the neat membrane. Filtration efficiency of ENCMs was evaluated using the submerged system with the humic acid (HA) solution. Results showed that the permeation flux of the membranes increased with an increase in the content of the γ-alumina NPs (from 49 to 102 L.m-2.h-1). The irreversible fouling ratio (IFR) of the membranes was also improved by increase in the content of the γ-alumina NPs up to 3 wt.%. Results also demonstrated the better anti-fouling performance for the blended nanofiber membrane with 3 wt.% of the nanoparticles (flux recovery ratio, FRR=94.4 %). HA rejection test also proved the enhanced foulant removal (99.6 %) of ENCM containing 3 wt.% γ-alumina NPs.

Computational modelling of a centrifugal technique for separating binary mixtures of thermoplastic polymers in the molten state is presented. The technique may be useful for the recycling of polymeric materials. The study investigates the physical process of component separation due to the centrifugal force in a batch process, showing the potential of using a dispersed model for describing the complex mechanism underlying the technique. Given the long time scales of change of the flow field, the polymer melts are modelled as inelastic, shear-thinning materials. The centrifugal force drives the component with the higher density to the outer region of an annular cross section occupied by the melt inside a rotating containment. The model system PET/LDPE is investigated in detail. The simulations allow to predict the process time needed for the separation. The simulations are the basis for studying a continuous process in a rotating tube.

In this research, diblock copolymers based on the rod segment of regioregular poly(3-hexylthiophene) (P3HT) and a coil segment of poly(2-(dimethylamino)ethyl methacrylate-random-1-pyrenylmethyl methacrylate) (P(DMAEMA-r-PyMA)) was synthesized successfully by Grignard metathesis (GRIM) method and atom transfer radical polymerization reaction (ATRP). The obtained copolymer was well-defined with an average molecular weight of 11300 g/mol and low polydispersity below 1.5. The polymer structure was determined via gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H NMR) spectroscopies. In addition, the optical and thermal properties of polymers were characterized via ultraviolet–visible (UV–Vis), differential scanning calorimetry (DSC) spectroscopy and fluorescence spectroscopy. Interestingly, P3HT-b-P(DMAEMA-r-PyMA) was examined as a possible chemosensor for trace detection of the trinitrotoluene (TNT) explosive.

In this study, we prepared composites of poly(benzaldehyde-co-thiophene) (PBT) and titanium oxide (TiO2) at varying rates of TiO2 (3%, 7%, and 10%). The copolymer was synthesized using the chemical oxidative polymerization method, and the composites were prepared by mixing PBT and TiO2 in dichloromethane at room temperature for 24 h. The materials were then analyzed using several techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction, UV/visible spectroscopy, and electrical conductivity measurements. The X-ray diffraction results revealed an amorphous structure of PBT and a semi-crystalline structure of the composites. The synthesis efficiency of the copolymer/TiO2 composites was confirmed by FTIR, while UV/visible spectroscopy was used to determine the optical properties of the PBT and composites. The results showed that the optical band gap of the PBT was 2.30 eV, which decreased to 2.19 eV with increasing TiO2 doping rate to 10%. The refractive index of the copolymer was 3.64 and decreased to 3.02 for the composite containing 3% of TiO2 before increasing again for the other two samples. Finally, the electrical conductivity of the copolymer and composites varied between 8.00 × 10–8 S.cm−1 and 3.40 × 10–4 S.cm−1.

Microstructure distribution in polyolefin resins is one of the key factors governing the macroscopic properties of the products. The chain microstructure of two transparent poly(propylene-co-1-butene) (PPB) resins is investigated in this study through temperature rising elution fractionation in the temperature range of 35 − 140 °C. Both resins contain small amount of room temperature soluble component, i.e. less than 3.80 wt% fractions eluted at 35 − 50 °C, implying that the two resins could be used as food containers or food packaging films safely with very low migration of soluble contents. The two resins exhibit remarkable differences in composition distributions as 41.24 wt% of resin PPB-1 was collected at 100 °C, whereas 58.24 wt% of resin PPB-2 was collected at 83 °C. The composition and sequence distribution in each fraction were analyzed by 13C NMR spectroscopy. All the fractions are random propylene/1-butene copolymers containing 1-butene concentration in the range of 2.7 − 7.6 mol% for resin PPB-1 and 2.2 − 8.5 mol% for resin PPB-2. Individual 1-butene unit is mainly inserted into the polypropylene main chains since the average sequence length of 1-butene (nB) is really short (1.0 − 1.3). Resin PPB-1 has more fractions with high molecular weight and isotacticity collected above 105 °C than resin PPB-2, which contributes to a better stiffness of resin PPB-1. Besides, the difference in haze for the films produced from resins PPB-1 and PPB-2 is also demonstrated based on the chain microstructure results. It is found that resin PPB-2 has higher MFR and longer propylene sequences than resin PPB-1, resulting in a higher haze.

Modifying natural rubber latex (NRL) and blending it with NRL can improve NRL performance and expand application fields. The performance of co-blended latex will change due to changes in non-rubber components during storage. Therefore, it is important to study the change of properties during the storage of co-blended latexes. In this paper, 30% methyl methacrylate grafted natural rubber (MG30) was synthesized by cumene hydroperoxide/ tetraethylenepentamine (CHPO/TEPA) initiating system, MG30 and NRL were mixed in different proportions to study the morphology and physical and mechanical properties, and the colloidal properties and emulsion properties of co-blended latexes were studied during storage. The results showed that the mechanical stability of NRL and co-blended latexes were high and the viscosity gradually increased during storage. The study of the vulcanization characteristics of the co-blended latexes films and the physical and mechanical properties of the vulcanized latex films showed that the vulcanization time of the co-blended films increased and the torque value increased in comparison to NRL. With the increase of MG30 content, the tensile strength and tear strength of the co-blended latexes vulcanized films showed a trend of increasing and then decreasing, and the co-blended film with 10% MG30 showed the best mechanical properties.