Antiplasticizing Effect of MOCA on Poly(vinyl chloride)

An obvious antiplasticizing effect has been observed in PVC with small amount of MOCA, 3,3’-dichloro-4,4’-diamino-diphenylmethane. PVC-MOCA interaction and crystallization behavior of PVC/MOCA blends were investigated in detail to explain the mechanism of antiplasticization on the basis of a series of techniques including DMA, FTIR, and DSC. The results of mechanical properties tests show that the tensile strength of PVC with 5 phr of MOCA reaches a maximum value, 69.5 Mpa, which is about 23 % higher than that of pure PVC. The rise in tensile strength was attributed to an antiplasticizing effect of MOCA on PVC as confirmed by DMA measurements. The evidences from FTIR reveal that a strong hydrogen-bonding interaction takes place between the nitrogen atom of –NH2 groups in MOCA and the methine proton of PVC repeat units. The results of DSC analysis indicate that crystallization behavior of MOCA is suppressed completely and the crystallinity of PVC decreases with the increase of MOCA amount.

Influence of Annealing and Additives on the Crystallization Behavior and Properties of Poly(vinyl chloride)

Acetanilide （AC）, adipic acid （AA） and potassium hydrogen phthalate （PHP） were chosen as additives to accelerate PVC crystallization and improve its mechanical properties. The influences of the additives and annealing on the crystallization behavior, micromorphology and the tensile properties were investigated by the thermal analysis, scanning electron microscopy （SEM） and the tensile test. Based on the analysis results, it was concluded that the melting peaks ranging from 110 to 200 ℃ and 200 to 240 ℃ were caused by the fusion of the fringed micelle crystals and chain-folded crystals respectively. AC advanced the fringed micelle crystal to develop, while AA and PHP promoted obviously the chain-folded crystal to grow. The addition of the foreign additives did not change the growth pattern ofPVC crystallites, the growth of the micelle crystal was favorable at 110 ℃, and the chain-folded crystal was developed at higher temperature. For PVC/ AA and PVC/PHP, when annealed at 110 ℃, a regular nest like network was formed, the crystallinity and the crystallite size were increased as well, and as a result, the tensile strength, Young＇s modulus and the elongation at break point were improved simultaneously and greatly.

A comparative study for petroleum removal capacities of the bacterial consortia entrapped in sodium alginate,sodium alginate/poly(vinyl alcohol),and bushnell haas agar

The purpose of this study was to identify and compare the degradation efficiencies of free and entrapped bacterial consortia(Staphylococcus capitis CP053957.1 and Achromobacter marplatensis MT078618.1)to different polymers such as Sodium Alginate(SA),Sodium Alginate/Poly(Vinyl Alcohol)(SA/PVA),and Bushnell Haas Agar(BHA).In addition to SA and SA/PVA,which are cost-effective,non-toxic and have different functional groups,BHA,which is frequently encountered in laboratory-scale studies but has not been used as an entrapment material until now.Based on these,the polymers with different surface morphologies and chemical compositions were analyzed by SEM and FT-IR.While the petroleum removal efficiency was higher with the entrapped bacterial consortia than with the free one,BHA-entrapped bacterial consortium enhanced the petroleum removal more than SA and SA/PVA.Accordingly,the degradation rate of bacterial consortia entrapped with BHA was 2.039 day^(-1),SA/PVA was 1.560,SA was 0.993,the half-life period of BHA-entrapped bacterial consortia is quite low(t_(1/2)=0.339)compared with SA(t_(1/2)=0.444)and SA/PVA(t_(1/2)=0.697).The effects of the four main factors such as:amount of BHA(0.5,1,1.5,2,2.5,3 g),disc size(4,5,6,7,8 mm),inoculum concentration(1,2.5,5,7.5,10 mL),and incubation period on petroleum removal were also investigated.The maximum petroleum removal(94.5%)was obtained at≥2.5 mL of bacterial consortium entrapped in 2 g BHA with a 7 mm disc size at 168 h and the results were also confirmed by statistical analysis.Although a decrease was observed during the reuse of bacterial consortium entrapped in BHA,the petroleum removal was still above 50%at 10th cycle.Based on GC-MS analysis,the removal capacity of BHA-entrapped consortium was over 90%for short-chain n-alkanes and 80%for medium-chain n-alkanes.Overall,the obtained data are expected to provide a potential guideline in cleaning up the large-scale oil pollution in the future.Since there has been no similar study investigating petroleum removal with the bacterial consortia entrapped with BHA,this novel entrapment material can potentially be used in the treatment of petroleum pollution in advanced remediation studies.

Development of a Poly(vinyl chloride)-based Nitrate Ion-selective Electrode

The authors developed a nitrate ion-selective electrode（ISE） based on poly（vinyl chloride）（PVC） membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nitrate-sensitive membranes was optimized by tuning the composition of components.The electrode exhibits a linear response with a Nernstian slope of（52±1.0） mV per decade for the nitrate ion concentration ranging from 5.8×10-5 mol/L to 1.0 mol/L.The electrode can be used to detect a low concentration of nitrate ions down to 3×10-5 mol/L in a pH range of 2.1―11.5 without any compensation.The advantage of the electrode includes simple preparation,short response time and good repeatability.The detection performance of the novel electrode on nitrate ions has been tested for water samples.

Analyzing Precipitation Acidity Changes Post Train Derailment and Vinyl Chloride Release in East Palestine, Ohio: Exploring Biomedical and Environmental Ramifications

This study investigates the aftermath of a significant train derailment and vinyl chloride release incident in East Palestine, Ohio, with a particular focus on the analysis of precipitation acidity changes and the concentration of vinyl chloride in samples. The research seeks to elucidate the complex relationship between industrial accidents, atmospheric chemistry, and their potential implications for human health and the environment. Through meticulous examination of variations in precipitation acidity patterns, this study provides valuable insights into the dispersion and impact of toxic agents in the environment following industrial mishaps. The results underscore the intricate interplay between these factors, highlighting the need for a multidisciplinary approach that bridges the realms of environmental science and biomedical concerns. This research contributes to a growing body of knowledge that addresses the broader consequences of industrial incidents on public health. It underscores the importance of proactive measures, such as enhanced monitoring and surveillance, risk assessment, public education, and regulatory reform, to mitigate the environmental and health risks associated with industrial activities involving hazardous materials. By fostering collaboration between experts and stakeholders, this study advocates for a holistic approach to safeguarding both our environment and the well-being of communities affected by industrial accidents.

Rare Earth Stearates as Thermal Stabilizers for Rigid Poly(vinyl chloride)

A series of stearates with different rare-earth ion were investigated as thermal stabilizers for rigid PVC at 180 ℃ in air. Their stabilizing efficiency was based on measuring the rate of dehydrochlorination. The resulted revealed the higher stabilizing efficiency of the investigated rare-earth stearates as thermal stabilizers for rigid PVC compared with the thermal stabilizers for industry: calcium stearate, zinc stearate, butyl stannum mercaptide, phosphite esters, β-diketone and epoxidized sunflower oil. This was well illustrated by longer incubation period (T_S) values and lower rate of dehydrochlorination. The stable efficiency was affected by the nature of rare-earth element's individual electronic shell. The mechanism for the stabilizing effect of rare-earth stearates was proposed. The result was experimentally proved based on IR spectrum.

Creep Behaviour of Wood Flour/Poly(vinyl chloride) Composites

The experimental creep data were focused on wood-flour （WF）/poly vinyl chloride （PVC） composites with the variations in additive concentrations of wood flour, silane coupling agent, organomodified montmorillonite （OMMT） and nano-cacium carbonate （nano-CaCO3）. Their effects were analyzed using the Four-element Burger Model incorporating microscopic mechanisms. Total creep strain was low with increasing WF while elastic strain was high and plastic flow strain was low in modeling. Modification of WF with silane was beneficial to creep resistance, so did adding low ratio of OMMT （1.5 wt%） and nano-CaCO3 in composites. Thus, it was effective in reducing creep either by stiffening the PVC matrix using rigid nano-particles or by improving their adhesion with resin. However, superfluous quantity of any additament did not benefit the improvement owing to either earlier destruction of their agglomerates or stress-concentrated cracks in the over-incrassated interface.

PARTICLE MORPHOLOGY OF POLY(VINYL CHLORIDE)RESIN PREPARED BY SUSPENDED EMULSION POLYMERIZATION

Suspended emulsion polymerization was used to prepare poly(vinyl chloride) (PVC) resin. Fine PVC particleswere formed at low polymerization conversions. The amount of fine panicles decreases as conversion increases anddisappears at conversions greater than 30%. Scanning electron micrographs show that PVC grains are composed of looselycoalesced primary particles, especially for PVC resins prepared in the presence of poly(vinyl alcohol) dispersant. The size ofprimary particles increases and porosity decreases with the increase of conversion. In view of the particle features of PVCresin, a particle formation mechanism including the formation of primary particles and grains is proposed. The formationprocess of primary particles includes the formation of particle nuclei, coalescence of particle nuclei to form primary particles,and growth of primary particles. PVC grains are formed by the coagulation of primary particles. The loose coalescence ofprimary particles is caused by the colloidal stability of primary particles and the low swelling degree of vinyl chloride in the primary particles.

Effect of phosphite and epoxy soybean oil on heat stability of poly （vinylchloride） composite stabilizers

The influences ofphosphite and epoxy soybean oil in combination with liquid calcium/zinc isocaprylates on the thermal stability of flexible poly （vinyl chloride） were studied. The stabilizing effect of poly （vinyl chloride） was evaluated by Congo red method, thermoaging test and Thermogravimetric-differential Scanning Calorimetry （TG-DSC）. The results showed that the addition of the phosphite or epoxy soybean oil improved the thermal stability of PVC with the calcium/zinc isocaprylates stabilizing system, especially epoxidied soybean oil exhibited a remarkable effect, and the synergism on PVC thermal stability for 3：2 phenyl dioctyl phosphite to epoxidized soybean oil weight ratio was acquired. Accordingly, the rapid mass loss in TG curve occured between 258.9 ℃ and 334.4 ℃, which corresponded to the enthalpy of the pyrogenation of 609.2 J/g. It was also found that the stabilized PVC of the best ratio gave better mechanical and processing properties.

Structures of LDHs Intercalated with Ammonia and the Thermal Stability for Poly(vinyl chloride)

MgAl-NH3 LDHs (layered double hydroxides), ZnAl-LDHs and ZnAl-NH3 LDHs with different molar ratio of Al/ammonia were synthesized by co-precipitation method. The synthetic LDHs samples were characterized by XRD, FT-IR, TGA-DTG and SEM techniques and tested by Congo red method. In addition, after PVC (Poly vinyl chloride) and DOP (Dioctylphthalate) were added to LDHs, the thermal stability for PVC was characterized by TGA-DTG. The results indicated that LDHs intercalated with ammonia improved thermal stability for PVC significantly, MgAl-NH3 LDHs (Mg2+:Al3+: NH3·H2O = 3:1:0.5) and ZnAl-NH3 LDHs (Zn2+:Al3+:NH3·H2O=2:1:1.5) showed the best thermal stability for PVC, interlayered space of LDHs became larger by intercalating ammonia.

Influence of Suspended Emulsion Polymerization Conditions on Particle Characteristics of Polyvinyl Chloride Resin

Suspended emulsion polymerization of vinyl chloride was carried out in a 5 L autoclave. The influence of agitation, polymerization conversion, dispersant and surfactant on the average particle size (PS) and particle size distribution (PSD), particle morphology and porosity of polyvinyl chloride (PVC) resin was investigated. It showed that the agitator had great influence on the smooth operation of polymerization, PS and PSD. The PS increased and PSD became narrow as polymerization conversion became high. The porosity decreased with the increase of conversion. A convenient choice of additives, both dispersants and non-ionic surfactants, allows one to adjust PS and PSD. The PS decreased with the addition of polyvinyl alcohol or hydroxypropyl methylcellulose dispersants,and increased with the addition of Span surfactants. The addition of dispersants or surfactants also affected the morphology and porosity of resin, and PVC resin with looser agglomeration and homogeneous distribution of primary particles was prepared.

UV enhanced gas–solid synthesis of chlorinated poly vinyl chloride characterized by a UV–Vis online analysis method

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly.Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature(Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.

Evaluation in vinyl chloride monomer-exposed workers and the relationship between liver lesions and gene polymorphisms of metabolic enzymes

AIM： To analyze occupational health hazards exposure to doses lower than the Chinese occupational health standard in a selected VC polymerization plant in China, and also to elucidate the relationship between genetic polymorphisms and genetic susceptibility on liver lesions of workers exposed to vinyl chloride monomer （VCM）. METHODS： In order to explore the mechanism of VCM- related health effects, we used a case-control design to investigate the association between the genetic polymorphisms of metabolic enzymes and liver lesions in workers occupationally exposed to VCM. Genotypes of CYP2E1, GSTT1, GSTM1, ALDH2 and ADH2 were identified using PCR and PCR-RFLP. RESULTS： Even when the concentration of VCM was lower than the current Chinese occupational health standard, neurasthenia, pharyngeal irritation, liver ultrasonography abnormalities and hemoglobin disorders were significantly higher in exposure subjects compared to non-exposure subjects, and the relative risks （RRand 95% C1） were 1.74 （1.06-2.85）, 1.97 （1.56-2.48）, 10.69 （4.38-26.12）, and 2.07 （1.20-3.57）. CYP2E1 c1c2/c2c2 genotype was significantly associated with liver damages （OR 3.29, 95% CI 1.51-7.20, P〈0.01）. CONCLUSION： The incidences of neurasthenia and liver ultrasonography abnormalities significantly increase when the cumulative exposure dose increases. The genotypes of metabolic enzymes （CYP2E1 c1c2/c2c2, null GSTT1 and ADH2 1-1） play important roles in VCM metabolism. Polymorphisms of CYP 2E1, GSTT1 and ADH2 may be a major reason of genetic susceptibility in VCM-induced hepatic damage.

Synthesis of CaZnAl-CO3 ternary layered double hydroxides and its application on thermal stability of poly(vinyl chloride)resin

In this work,hydrothermal method was used to prepare the CaZnAl-CO3 ternary layered double hydroxides(CaZnAl-CO3-LDHs)with various Ca/Zn/Al molar ratios,which were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscope(FT-IR)and scanning electron microscopy(SEM)techniques.The obtained results demonstrate that the samples were well-crystallized and flake-structured.The CaZnAl-CO3-LDHs used alone for thermal stability of poly(vinyl chloride)(PVC)resin,with different Ca/Zn/Al molar ratios and varying additive amounts,were investigated through the tests such as static thermal aging,mass loss and congo red,respectively.The optimum Ca/Zn/Al molar ratio and additive amount were 3.6:0.4:2 and 5 phr(parts per hundred PVC resin),respectively.In addition,the synergistic effects of Ca3.6Zn0.4Al2-CO3-LDHs and CaSt2 were discussed in detail,showing better thermal stability compared with Ca3.6Zn0.4Al2-CO3-LDHs used alone,and the optimum additive amounts of Ca3.6Zn0.4Al2-LDHs and CaSt2 were 6 and 1.0 phr,respectively.

Synthesis of Bio-Plasticizer from Soybean Oil and Its Application in Poly(Vinyl Chloride) Films

Herein,epoxidized soybean oil methyl ester(ESOM)plasticizer was synthesized for the preparation of plasticized poly(vinyl chloride)(PVC)films by the alcoholysis and epoxidation.The chemical structure of ESOM was investigated by infrared spectrum and 1 H nuclear magnetic resonance.The effect of content of ESOM and petroleum based plasticizer di-2-ethylhexyl phthalate(DEHP)on the performance of plasticized PVC films was studied.The result showed that substituting DEHP with ESOM can improve the thermal stability of plasticized PVC films.When the weight ratio of ESOM and PVC is fixed at 1:2,plasticized PVC film presents higher elongation at break(350.8%vs.345.1%)and lower tensile strength(14.21 MPa vs.15.8 MPa)compared with PVC plasticized with DEHP.ESOM showed less weight loss than DEHP in all solvents.The excellent migration resistance of ESOM is helpful to improve stability of plasticized PVC films.In all,the obtained bio-based plasticizer will be potential to replace petroleum based plasticizer DEHP in flexible PVC materials.

PHASE EQUILIBRIUM FOR THE TERNARY SYSTEM VINYL CHLORIDE-CHLORINATED POLYETHYLENE-POLY(VINYL CHLORIDE)

Swelling capacity of vinyl chloride (VC) in chlorinated polyethylene (CPE) with 25—40 wt% Cl at temperature 30—57℃ was studied and their relationships were correlated with Langmuir and Freundlich adsorption equations. A ternary phase diagram for VC-CPE-PVC was also established. In-situ polymerization conditions of CPE-g-VC were proposed and CPE content control was analyzed for the manufacturing process of CPE-g-VC graft product based on results of phase equilibrium study.

Microstructure and Mechanical Properties of Poly (Vinyl Chloride) Modified by Silica Fume /Acrylic Core-Shell Impact Modifier Blends

This research explored replacing acrylic core-shell impact modifier （AIM） by silica fume to toughen PVC. 100%, 75%, 50% and 25% of AIM （8 phr） were substituted by silica fume in PVC respectively, and then processed by dry blending and twin-screw extrusion. Severe silica fume agglomeration was observed by scanning electron microscope （SEM） in the PVC matrix when 8 phr pure silica fume was used and processed by screw speed of 20 rpm. Its tensile strength was thereby reduced by 38% comparing to unmodified PVC. The silica fume was successfully dispersed while the screw speed was slowed down to 10 rpm to give a stronger screw torque and a longer melt residential time in the extruder. The tensile strength was ’recovered’ to a level comparable to unmodified PVC. Impact test were performed on all formulations extruded at 10 rpm screw speed and synergetic toughening effect was found with 50% substitution and it had the impact strength that was comparable to 8 phr pure AIM toughened PVC.

Preparation of MgAl LDHs Intercalated with Amines and Effect on Thermal Behavior for Poly(vinyl chloride)

MgAl LDHs intercalated with CO(NH2)2, NH4Cl and NH3·H2O were prepared by co-precipitation and XRD, FT-IR, TGA-DTA and SEM techniques were employed for characterization. The results indicated that the layer-layer spacing of LDHs was enlarged by 0.169, 0.285 and 0.227 Åwith the intercalation of CO(NH2)2, NH+4 and NH3, separately. The effects on thermal stability and degradation behavior of synthesized LDHs where mole ratios of Mg/Al/urea = 3:1:1, Mg/Al/NH4Cl = 3:1:1.5 and Mg/Al/NH3·H2O = 3:1:0.5 were investigated by Congo Red Method and thermogravimetric analysis (TGA) from 25°C - 800°C under N2. The TGA and DTA results showed, by incorporating 5% MgAl-CO(NH2)2 LDH, the dehydrochlorination temperature of PVC composites is 12°C higher than MgAl-NH+4 and MgAl-NH3 LDHs. MgAl-NH3 LDH enhances the ending temperature of the first degradation stage of PVC composites by 8°C compared with MgAl LDH. The LDH intercalated with CO(NH2)2 is proved to be an effective thermal stabilizer for PVC processing.