Compressive Performance of Fiber Reinforced Recycled Aggregate Concrete by Basalt Fiber Reinforced Polymer-Polyvinyl Chloride Composite Jackets

The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding basalt fibers(BFs)and using external restraints,such as a fiber-reinforced polymer(FRP)jacket or a PVC pipe.Samples were tested under axial compression.The results showed that RAC(50%replacement of aggregate)containing 0.2%BFs had the best mechanical properties.Using either BFs or PVC reinforcement had a slight effect on the loadbearing capacity and mode of failure.With different levels of BFs,the compressive strengths of the specimens reinforced with 1-layer and 3-layer basalt fiber reinforced polymer(BFRP)increased by 6.7%–10.5%and 16.5%–23.7%,respectively,and the ultimate strains increased by 48.5%–80.7%and 97.1%–141.1%,respectively.The peak stress of the 3-layer BFRP-PVC increased by 42.2%,and the ultimate strain improved by 131.3%,relative to the control.This reinforcement combined the high tensile strength of BFRP,which improved the post-peak behavior,and PVC,which enhanced the structural durability.In addition,to investigate the influence of the various constraints on compressive behavior,the stress-strain response was analyzed.Based on the analysis of experimental results,a peak stress-strain model and an amended ultimate stress-strain model were proposed.The models were verified as well;the result showed that the predictions from calculations are generally consistent with the experimental data(error within 10%).The results of this study provide a theoretical basis and reference for future applications of fiber-reinforced recycled concrete.

Phosphorus Containing Rubber Seed oil as a Flame Retardant Plasticizer for Polyvinyl Chloride

The application of phthalate plasticizers has been restricted around the world due to their poor migration and potential harm to the human body.Hence,producing functional bio-based plasticizers via exploiting clean and reusable resources meets the satisfaction of current demands.In this study,flame-retardant rubber seed oil-based plasticize(FRP)was prepared via epoxidation reaction and ring opening addition reactions,which was used as a flame-resistant plasticizer for polyvinyl chloride to replace petroleum-based phthalate plasticizer.When DOP was replaced with FRP,the torque of PVC blends increased from 11.4 to 18.4 N⋅m,the LOI value increased from 24.3%for PVC-FRP-0%to 33.1%for PVC-FRP-20.The THR value diminished from 39 MJ/m^(2)(pertaining to PVC-FRC-0)to 22 MJ/m^(2)Tg increased from 23°C to 47°C,the weight loss of plasticized PVC blends significantly reduced from 22.6%to 2.8%in leaching tests.The study provided a new way to prepare flame retardant plasticizer using rubber seed oil as raw material.

The Influence of Additives on Crystallization of Polyvinyl Chloride

Acetanilide, adipic acid and potassium hydrogen phthalate were chosen as nucleating agents of polyvinyl chloride（PVC）, and their effects on PVC crystallization were studied by differential scanning calorimetry, wide angle X-ray diffraction and fourier transform infrared spectroscopy. The experimental results indicate that all of the three additives are compatible with PVC to some extent, but adipic acid＇s compatibility with PVC is less satisfactory. The three additives can improve PVC crystallinity, and acetanilide can decrease PVC glass transition temperature（T）and narrow PVC melting range, while adipic acid and potassium hydrogen phthalate rise T of PVC and widen its melting range. All additives do not affect PVC crystal system and all g samples are in orthorhombic system. All additives can improve （200）, （110）, （210） and （201, 111） planes growing. Moreover, acetanilide and adipic acid can shrink PVC spacings and improve the crystal perfection of PVC, but potassium hydrogen phthalate swells spacings and reduces the perfection of PVC crystal.

Surface Sulfonation of Polyvinyl Chloride by Plasma for Antithrombogenicity

To enhance the blood compatibility of Polyvinyl Chloride (PVC) film, the film was modified by SO2/O2 gas plasma treatment. The effect of surface sulfonation of PVC treated by various SO2/O2 gas plasma depended on the volume ratio O2/(SO2 +O2). When the volume ratio was 0.5, the effect of sulfonation was the best. Sulfonic acid groups were specifically and efficiently introduced onto the PVC surface, which was proved by X-ray photoelectron spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transfer Infrared (ATR-FTIR) spectroscopy. The surface microstructure of modified PVC film was studied with scanning electron microscopy (SEM). The antithrombogenicity of the samples was determined by the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and plasma recalcification time (PRT) tests and platelet adhesion experiment. The results indicated that the antithrombogenicity of modified PVC was improved remarkably.

SYNERGISTIC MODIFICATION OF EPDM AND CROSSLINKING AGENT IN IMMISCIBLE BLENDS OF POLYVINYL CHLORIDE WITH LOW DENSITY POLYETHYLENE

The synergism of ethylene-propylene-diene monomer copolymer （EPDM） and dicumyl peroxide （DCP, a crosslinking agent） in low density polyethylene （LDPE）/poly（vinyl chloride） （PVC） blends was investigated. When EDPM and DCP are added to the blends simultaneously, the tensile properties could be improved significantly, especially for the blends with LDPE matrix. For example, incorporation of 10/1 （mass ratio） EPDM/DCP improves the tensile strength of the LDPE/PVC （mass ratio 80/20） blend from 7.9 MPa to 8.5 MPa and the elongation at break from 25% to 503%. Results from selective extraction, phase-contrast microscopy and thermal analysis reveal that the improvement in the tensile properties of the blends with LDPE matrix is principally due to the formation of a fine crosslinking network of the LDPE and EPDM phase. The outstanding modification effect of EPDM is explained by its dual functions： molecular entanglement with LDPE and the enhanced efficiency of DCP in the blends.

Molecular Dynamics Simulation Studies on the Cooling Process of Polyvinyl Chloride

By means of molecular dynamics simulation, the transition of the conformations of polyvinyl chloride during a cooling process from 600 to 300 K was studied. The results show that the amorphous polyvinyl chloride chain experiences the melting state, elastic state and glass state and the conformations can be characterized by the increases of the trans-state of C--C--C--C and the near gauche-state of C--C--C--C1 with the decrease of temperature. It is found that the transition of the conformations is driven mainly by the Coulomb interaction between chain segments.

STUDY ON THE MORPHOLOGY OF POLYVINYL CHLORIDE/POLYSTYRENE BLENDS BY ELECTRON MICROPROBE ANALYSIS

The morphology of polyvinyl chloride/polystyrene (PVC/PS) blend samples with different mass ratios, prepared by means of solution casting and melt mixing, have been successfully examined by electron microprobe analysis (EMP). This experiment was performed in a scanning electron microscope attached to an energy dispersive X-ray analyzer. Differential scanning calorimetry was also used to investigate the phase separation of the blends. The results show that PVC and PS are incompatible and the blends have sea-islands phase structures. Blends prepared via melt mixing have finer phase-dispersion than those prepared via solution casting.

Toxicity mechanisms of photodegraded polyvinyl chloride nanoplastics on pea seedlings

Nanoplasctics(NPs),which are very small in particle size,exert toxic effect to organisms.Additionally,compared to original NPs,photodegraded NPs would pose higher toxicity.This is because their relatively higher specific surface areas and the presence of additives which can more easily leach.How original NPs and aged NPs affect plant growth has not been widely investigated.This work chose polyvinyl chloride NPs(PVC-NPs)that were subjected to up to 1000 h UV light radiation to explore the impact of PVC-NPs on the growth of pea seedlings(Pisum Sativum L.).The results indicated the existence of PVC-NPs with longer UV light radiation time and higher concentrations had more negative influences on pea seedlings’growth such as germination rate(decreased by 10.6%–22.5%),stem length(decreased by 2.8%–8.1%),dry weight(decreased by 6.3%–7.1%)and fresh weight(decreased by 6.7%–14.8%).It was also noted that photodegraded PVC-NPs resulted in damage to leaf stomata and roots,hindering photosynthesis and absorption of nutrients and hence the decrease in chlorophyll and soluble sugar contents.According to transcriptomic investigation results,the presence of aged PVC-NPs primarily influenced protein processing in endoplasmic reticulum(upregulated metabolic pathway)and phenylpropanoid biosynthesis(downregulated metabolic pathway)of pea seedlings.These results provide an in-depth understanding of how NPs influence the growth of plants.

EFFECT OF POLYANILINE AS A SURFACE MODIFIER OF TiO_2 NANO-PARTICLES ON THE PROPERTIES OF POLYVINYL CHLORIDE/TiO_2 NANOCOMPOSITES

Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.

Preparation of a Crosslinked Chitosan Coated Calcium Sulfate Whisker and Its Reinforcement in Polyvinyl Chloride

A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both chitosan （CS） and glutaraldehyde （GA） is 0.05 wt%. The tensile strength, impact strength, flexural modulus and vicat softening temperature of the PVC composite with 12 wt% of modified CSW are in- creased by 1 Z5%, 40.4%, 0.8% and 3.8% compared with those of the PVC composite with 12 wt~ of unmodified CSW, and by 2.9%, 42.4%, 2Z1% and 6.8% compared with those of pure PVC, respectively. The dynamic mechanical analysis results indicate that the modified CSW/PVC composite exhibits much higher storage modulus and glass transition temperature than those of unmodified CSW/PVC composite and pure PVC. In addition, the modified CSW/PVC composite also demonstrates good thermal properties with a high rapidest decomposition temperature （Trvd） and char residue. The scanning electron microscopy images of tensile-fractured surfaces show that the modified CSW has a strong interfacial adhesion with PVC matrix.

Enhancement of Photocatalytic Degradation of Polyvinyl Chloride Plastic with Fe_(2)O_(3) Modified AgNbO_(3) Photocatalyst under Visible-light Irradiation

The solid-phase photocataKtic degradation of polyvinyl chloride(PVC)plastic with AgNbO_(3)/Fe_(2)O_(3) is studied under visible-light irradiation.The PVC-(AgNbO_(3)/Fe_(2)O_(3))samples are characterized by X-ray photoelectron spectroscope(XPS),scanning electron microscope(SEM),gas chromatography(GC),and UV-vis diffusion reflectance spectra(UV-vis DRS).The photocatalytic properties of PVC-(AgNbO_(3)/Fe_(2)O_(3))samples are systematically investigated.More amounts of generated CO2,greater texture change and higher weight loss rate were exhibited in the system of PVC-(AgNbO_(3)/Fe_(2)O_(3))than pure PVC film.The weight loss rate is ten times higher than that of pure PVC film,which reaches to 46.53%with optimum amount of O.5wt% Fe_(2)O_(3).Active radicals generate primarily on the surface of Fe_(2)O_(3) particles,which cause composite plastic decomposition on the PVC-(AgNbO_(3)/Fe_(2)O_(3))interface and extend into polymer interor.The study provides a new promising way to degrade the plastic waste under visible-light.

Comparative study on the efficiency and environmental impact of two methods of utilizing polyvinyl chloride waste based on life cycle assessments

Two processes of utilizing polyvinyl chloride （PVC） waste, an incineration process and a vacuum pyrolysis process, for energy conversion were compared to determine their efficiency and environmental perfor- mance. We carried out a life cycle assessment with each of the two processes to evaluate their environmental impact and defined the goals and limits of our remit. As well, we established an inventory of PVC waste from incineration and vacuum pyrolysis based on process analysis, data collection and calculations. The results show that electrical power output per unit mass of PVC waste in the incineration process was twice as high as that of the vacuum pyrolysis process. Incineration had a larger total environmental impact potential than vacuum pyrolysis. The total environmental impact potential of PVC waste from incineration was three times higher than that from vacuum pyrolysis. Incineration of PVC disposed 300 ng. 100 kgI of dioxins and vacuum pyrolysis 98.19 ng- 100 kgI of dioxins. As well, we analyzed the data for their uncertainty with results quantified in terms of three uncertainties： basic uncertainty, additional uncertainty, and computational uncertainty. The coefficients of variation of the data were less than 25% and the quality of the inventory data was acceptable with low uncertainty. Both PVC waste disposal processes were of similar quality and their results comparable. The results of our life cycle impact assessment （LCIA） showed considerable reliability of our methodology. Overall, the vacuum pyrolysis process has a number advantages and greater potential for development of PVC disposal than the incineration process.

INFLUENCE OF LANTHANUM STEARATE AND CALCIUM/ZINC STABILIZERS ON STABILIZATION EFFICIENCY OF DIBUTYLTIN DILAURATE TO POLYVINYL CHLORIDE

Influences of lanthanum stearate （LaSt3） and calcium stearate/zinc stearate （Ca/Zn） stabilizers on stabilization efficiency of dibutyltin dilaurate （DBTDL） to polyvinyl chloride （PVC） in air were investigated. The results revealed that the stabilization effect of DBTDL could be achieved by the La/Sn stabilizers with a ratio of 8/2. Addition of DBTDL could enhance thermal property and reduce dynamic storage modulus （G＇） at 180℃ for PVC containing LaSt3 or Ca/Zn stabilizers. On the other hand, incorporation of LaSh did not influence the stabilization efficiency of DBTDL markedly; while addition of Ca/Zn stabilizers could significantly decrease thermal property for the DBTDL stabilized PVC. Furthermore, the effects of LaSt3 and Ca/Zn stabilizers on the stabilization efficiency of DBTDL were explained in the framework of ionization potential.

Gasification kinetics of char formed from waste polyvinyl chloride for efficient utilization in ironmaking process

In the prevailing incineration processes of municipal solid waste,the presence of polyvinyl chloride(PVC)may cause environmental problems.The energy-intensive ironmaking sector in the iron and steel industry operates at high temperature and under high reduction potential with the function of energy conversion,which can provide a potential path for the collaborative utilization of waste plastics in large quantities and low cost.The gasification of the char formed from PVC when processed in the ironmaking sector is significant for the development of the related technologies.Thus,the gasification experiment of PVC char and traditional carbonaceous materials was performed by thermogravimetric analysis.The results indicated that the gasification ability decreased in the sequence of PVC char>anthracite coal>coke>graphite.Then,kinetics were also analyzed by Coats-Redfern and Doyle approximations.The PVC char showed the best gasification ability with the smallest activation energy,ranging from 87.18 to 117.52 kJ/mol,and the smaller graphitization degree of PVC char compared with other carbonaceous materials should be the main reason for its excellent gasification reactivity.

Synthesis and Characterization of Phenyl Camellia oleifera Seed Oil Ester Plasticizing PVC

Plasticizers are essential additives in the processing of polyvinyl chloride(PVC),with phthalate plasticizers being widely used.However,these conventional plasticizers have been shown to be harmful to human health and environmentally unfriendly,necessitating the exploration of eco-friendly bio-based alternatives.In this study,Camellia oleifera seed oil,a specialty resource in China,was utilized as a raw material and reacted with 4,4′-Methylenebis(N,N-diglycidylaniline)(AG-80)to synthesize Phenyl Camellia seed Oil Ester(PCSOE).PCSOE was employed as a plasticizer to prepare modified PVC films with varying concentrations,with the conventional plasticizer dioctyl phthalate(DOP)serving as a control.Experimental results demonstrate that PSCOE-plasticized PVC films exhibit enhanced hydrophilicity,tensile strength,and thermal stability compared to DOP-modified PVC films.The contact angle of PSCOE-plasticized PVC films ranges from 66.26°to 78.48°,which is generally lower than the contact angle of DOP-modified PVC films at 78.40°,indicating improved hydrophilicity due to the modification with PCSOE.The tensile strength of PSCOE-plasticized PVC films ranges from 17.73 to 20.17 MPa,all surpassing the value of 16.41 MPa for DOP-modified PVC films.Moreover,the temperatures corresponding to 5%,10%,and 50%weight loss for PVC samples modified with PCSOE are higher than those for DOP.Hence,PCSOE presents a viable alternative to DOP as a plasticizer for PVC materials.

Synergistic Modification of PVC with Nitrogen-Containing Heterocycle and Tung-Oil Based Derivative for Enhanced Heat Stabilization and Plasticization Behavior

The additives present in polyvinyl chloride(PVC)materials are the major source of organic by-products during PVC degradation.The thermal stabilizer and plasticizer are the main additives that endow PVC with the required properties during its processing.However,these two additives easily migrate when samples are obtained by physical mixing of the additives with PVC.This causes the reduction of PVC sample efficacy and the increase in the formation of organic by-products in the radiolysis process.In this work,two kinds of grafted PVC samples(tungoil derivative grafted PVC and Atz grafted PVC,abbreviated as P-GT4 and P-AZ3)were synthesized by chemical grafting of 3-amino-1,2,4-triazole(Atz)and tung-oil derivative on PVC,respectively.These two PVC samples were then blended at different mass ratios to obtain hybrid PVC materials with excellent plasticization,thermal stability and migration resistance ability.Differential scanning calorimetry(DSC),discoloration,Congo red test and thermogravimetric analysis(TGA)showed that when the mass ratio of P-GT4 to P-AZ3 in the mixed PVC resin was 1:3,the resulting P1:3-GT4-AZ3(P4)presented the best plasticization and thermal stability.The kinetics of thermal decomposition showed that the activation energy of P4 was much higher than that of the reference material[PVC/DOTP/CaSt2/ZnSt2,PVC/CZ41 for short]at mass lossα=20%and 80%.In addition,the leaching test showed that P4 material possessed excellent migration resistance ability.

Plasticizing Effect of Camellia oleifera Seed-Oil-Based Plasticizer on PVC Material Modification

In this study,as the plasticizer,Camellia oleifera seed-oil-based cyclohexyl ester(COSOCE)was prepared by the reaction of cyclohexene oxide and refined C.oleifera seed oil(RCOSO)obtained by acidification hydrolysis after saponification.In addition,the structure of the target product was confirmed by Fourier transform infrared(FTIR)spectroscopy,nuclear magnetic resonance(NMR)spectroscopy,and Raman spectroscopy.COSOCE was used as plasticizer-modified polyvinyl chloride(PVC)membranes.The structure of the COSOCE-modified PVC membranes were characterized by Raman spectroscopy and scanning electron microscopy(SEM).The properties of the COSOCE-modified PVC membrane were characterized by contact angle measurements,universal testing machine,thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC).The results revealed that(1)The COSOCE-modified PVC membranes exhibit a good microscopic morphology.Combined with energy-dispersive X-ray spectroscopy(EDS)and contact angle measurement results,the COSOCE-modified PVC membranes are confirmed to be a hydrophilic material.(2)The modified PVC membrane with 60%COSOCE exhibited the best mechanical properties.The tensile strength reached 23.56±2.94 MPa.(3)COSOCE-modified PVC material exhibited better thermal stability,with a loss rate of less than 75%at the end of the first decomposition stage.Compared with that of the dioctyl-phthalate(DOP)-modified PVC membrane,the initial decomposition temperature of PVC was increased by 1.17°C–8.17°C,and the residual rate was increased by 0.67%–5.75%.The carbon–carbon double bond in the COSOCE molecular structure can remove the free radicals generated during the degradation of PVC material and slow down the decomposition rate of PVC.In addition,the double bond can be cross-linked partially with the PVC molecular chain containing the conjugated polyene structure,thereby increasing the movement resistance of the PVC molecular chain segment.Hence,COSOCE can replace DOP as a PVC plasticizer.

Numerical study on mixing performance of screw elements in intermeshing counter-rotating and co-rotating twin-screw extrudes

The flow process of unplasticized polyvinyl chloride （U PVC） through the mixing zone of intermeshing counter rotating and co rotating twin screw extruders （TSEs） were numerically simula ted by the finite element method. Three dimensional isothermal flow field of U-PVC in two kinds of TSE was calculated. The mixing performance of the screw elements of the extruders was statistically analyzed by particle tracking method. The dispersive mixing performance was characterized by the mixing index, the logarithm of stretching, and the segregation scale. The distributive mixing per forulance was characterized by the resident time distribution. The results indicate that the counter rotating TSE can build higher pressure and generate higher axial velocity and shear rate, whereas the co rotating TSE has better performance in dispersive and distributive mixing.

Creep performance of PVC aged at temperature relatively close to glass transition temperature

In order to predict the mechanical performance of the polyvinyl chloride （PVC） at a high operating temperature, a series of short-term tensile creep tests （one- tenth of the physical aging time） of the PVC are carried out at 63 ℃ with a small constant stress by a dynamic mechanical analyzer （DMA）. The Struik-Kohlrausch （SK） formula and Struik shifting methods are used to describe these creep data for various physical aging time. A new phenomenological model based on the multiple relaxation mechanisms of an amorphous polymer is developed to quantitatively characterize the SK parameters （the initial creep compliance, the characteristic retardation time, and the shape factor） determined by the aging time. It is shown that the momentary creep compliance curve of the PVC at 63℃ can be very well fitted by the SK formula for each aging time. However, the SK parameters for the creep curves are not constant during the aging process at the elevated temperatures, and the evolution of these parameters and the creep rate versus aging time curves at the double logarithmic coordinafes have shown a nonlinear phenomenon. Moreover, the creep master curves obtained by the superposition with the Struik shifting methods are unsatisfactory in such a case. Finally, the predicted results calculated from the present model incorporating with the SK formula are in excellent agreement with the creep experimental data for the PVC isothermally aged at the temperature relatively close to the glass transition temperature.

Preparation and Characterization of PVC/PAN Membrane Used as Medical Exhaust Membranes

The wet phase inversion process was used to prepare a kind of medical exhaust membranes with super-hydrophobicity and good gas permeability capacity by using non-woven fabric as the support base.The influences of solution temperature,the evaporation time,the content of the non-solvent additive and the ratio of polyvinyl chloride(PVC)/polyacrylonitrile(PAN) on the gas permeability capacity and hydrostatic pressure of the resultant membranes were investigated.A kind of composite membrane with gas permeability about 2 800 mL/min and hydrostatic pressure of 36 kPa was obtained.In addition,the relationship between the properties and structure of the membrane was analyzed.