Thermal Decomposition of Polymer Mixtures Containing Poly(vinyl chloride)

Thermal decomposition of a series of 1 : 1 mixtures of typical polymer waste materials [polyethylene (PE), poly(propylene) (PP), polystyrene (PS), polyacrylonitrile (PAN), polyisoprene, poly(methyl methacrylate) (PMMA), polyamide‐6 (PA‐6), polyamide‐12 (PA‐12), polyamide‐6,6 (PA‐6,6), and poly(1,4‐phenylene terephthalamide) (Kevlar)] with poly(vinyl chloride) (PVC) was examined using thermal analysis and analytical pyrolysis techniques. It was found that the presence of polyamides and PAN promotes the dehydrochlorination of PVC, but PVC has no effect on the main decomposition temperature of polyamides. The hydrogen chloride evolution from PVC is not altered when other vinyl polymers or polyolefins are present. The thermal degradation of PAN is retarded significantly, whereas that of the other vinyl polymers is shifted to a slightly higher temperature in the presence of PVC. Among the pyrolysis products of PAN‐PVC mixture methyl chloride was found in comparable amount to the other gaseous products at 500°C pyrolysis temperature.     

The effect of plastic addition on coal caking properties during carbonization

The recycling process of waste plastics using coke ovens is now being studied. The effect of plastic addition on coal caking property was investigated. It was revealed that thermal decomposition products of plastics interacted with bituminous coal during carbonization in coke ovens. The effect of plastic addition on coal caking property varied with types of plastics. The addition of aliphatic polymers such as polyethylene (PE), polypropylene (PP) and poly(vinyl chloride) (PVC) had only a small effect on coal caking property and coke strength and in some cases PE addition increased coke strength. On the other hand, the addition of polystyrene (PS), poly(ethylene terephthalate) (PET) and terephtalic acid (TFA) inhibited coal expansion and fusion, decreased maximum fluidity and total dilatation, and deteriorated the coke strength. These differences were discussed from the viewpoint of the interaction between thermal decomposition products of plastics and hydrogen in coal. It was suggested that the radical formed as a result of PS or PET thermal decomposition abstracted hydrogen from coal, which resulted in the decrease in coal caking property.     

Polymer blends containing poly(vinylidene fluoride). Part III: Polymers containing ester,ketone, or ether groups

To further investigate the nature of the specific interaction leading to the miscibility of poly(vinylidene fluoride), PVF₂, with certain oxygen containing polymers, blends of PVF₂ with poly(ε-caprolactone), PCL, with poly(vinyl methyl ether), PVME, and with poly(vinyl methyl ketone), PVMK, were prepared. PVMK/PVF₂ blends were found to be miscible while blends of PVME/PVF₂ and PCL/PVF₂ were found not to be miscible. These results show that the specific interaction with PVF₂ involves mainly the carbonyl group rather than the entire ester group. The relative effectiveness of having this group in the chain or pendant to it is not yet resolved.     

聚合物共混物的红外光谱研究

采用傅立叶变换红外光谱（FTIR）技术，同时将谱图进行归一化处理，通过合谱共混谱研究了氯丁橡胶（CR）／聚氯乙烯（PVC）和CR／聚苯乙烯（PS）两个二元聚合物共混体系的相容性，结果表明，CR与PVC所组成的共混物中组分矣合物红外光谱特征吸收谱带发生较大位移，表现出较强的相互作用，CR与PS所组成的共混物的红外吸收特征峰发生了较小偏移，同时特征峰形略有变化，说明有较弱的相互作用。     

Upcycling of polypropylene—the influence of polyethylene impurities

Long chain branching (LCB)—a well‐known industrial process—is shown as an innovative tool for the treatment of PP post‐consumer waste. The introduction of LCB by reactive extrusion does not only compensate the degradation during product life (e.g., thermally and UV‐induced chain scission), it also improves the melt properties (e.g., melt strength, strain hardening). Thus, not only a re‐cycling process, even a real “up‐cycling” can be achieved. Compared with virgin material, PP from post‐consumer waste contains impurities like other polyolefines (PE‐HD, PE‐LD, PE‐LLD, copolymers), the total removal is economically not viable. Hence, the focus of this work was the influence of PE‐HD on the LCB formation of PP. Based on model mixtures with virgin PP and 10% PE‐HD, it is shown that PE‐HD influences the mechanical properties and gel content of the chemically modified blend but has no detrimental effect on the improved melt properties. POLYM. ENG. SCI., 57:1374–1381, 2017. © 2017 Society of Plastics Engineers     

Polymer blends containing poly(vinylidene fluoride). Part II: Poly(vinyl esters)

Blends of poly(vinylidene fluoride) PVF₂, with poly(vinyl acetate), PVAc; with poly(vinyl propionate), PVPr; and with poly(vinyl butyrate), PVBu, were prepared by solution blending. Solutions containing PVF₂ with either PVPr or PVBu exhibited phase separation, and it was concluded that neither of these polymers are miscible with PVF₂. Phase separation did not occur with solutions containing PVF₂ and PVAc. Dried samples of this blend system were subjected to differential thermal analysis, dynamical mechanical testing, and visual observations of their melts. From these results, it was concluded that PVF₂ and PVAc are miscible. The detailed results and the structural implications of these observations are discussed.     

Chlorinated poly(vinylidene fluoride)

Chlorinated poly(vinylidene fluoride) (PVF₂) was prepared by introducing chlorine gas into a CCI₄ suspension of PVF₂ at reflux temperature. Polymer crystallinity and softening point decrease, while solubility and adhesion increase with the degree of chlorination. In contrast to PVF₂, the chlorinated polymer is soluble in low-boiling common organic solvents, such as acetone, methyl ethyl ketone, and 1,2-dimethoxyethane. Chlorinated PVF₂ is resistant to dehydrochlorination and is thermally more stable than PVF, chlorinated PVF, PVC, or chlorinated PVC. Chlorinated PVF₂ coatings on wood, prepared by solution casting at room temperature, show outstanding weathering resistance.     

Effect of sepiolite on glass transition temperature and melting behaviour of semicrystalline polymer blends

Summary Thermal analysis of blends poly(vinylidene fluoride) (PVF₂) with poly(methyl methacrylate) (PMMA) or polystyrene (PS) filled with sepiolite was carried out to examine the effects of the filler on properties such as melting behaviour and glass transition temperature. For the compatible PVF₂/PMMA system, the presence of the filler did not cause any substantial changes in the thermal behaviour of the blend. In the non-compatible PVF₂/PS system, some compatibilization is achieved in the blend, indicated by PVF₂ melting point depression as well as by a shift of the glass transition of the homopolymers in the blend.     

Application of equation of state and artificial neural network to prediction of volumetric properties of polymer melts

The modified ISM EOS and artificial neural network (ANN) methods were used to predict the PVT behavior of polymer melts containing polystyrene (PS), polycarbonate bisphenol-A (PC), polyvinylidene fluoride (PVDF), polypropyleneglycol (PPG), polyethylene glycol (PEG), polypropylene (PP), poly vinylchloride's properties (PVC), poly(1-butene) (PB1), polycaprolactone (PCL), polyethylene (PE) and polyvinyl methyl ether (PVME) over the entire range of available temperature and pressure. The obtained results show that the modified ISM EOS and ANN models have good agreement with the experimental data with mean average absolute deviation of 0.58% and 0.20%, respectively.     

Miscibility of linear low density polyethylene (LLDPE)-graft-poly(methyl methacrylate) with poly(vinylidene fluoride) (PVF2) and its application as compatibilizer LLDPE/PVF2 blends

Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to study the miscibility of blends of a graft copolymer of poly(methyl methacrylate) on linear low density polyethylene (LLDPE-g-PMMA, G-3) with poly(vinylidene fluoride)

1 Systematic name: poly(1,1-difluoroethylene).

(PVF₂) and the compatibilization of blends of LLDPE/PVF₂. The specific interaction between PMMA side chains and PVF₂ in G-3/PVF₂ binary blends is weaker than that between the homopolymers PMMA and PVF₂. There are two states of PVF₂ in the melt of a G-3/PVF₂ (60/40, w/w) blend, one as pure PVF₂ and the other interacting with PMMA side chains. The miscibility between PMMA side chains and PVF₂ affects the crystallization of PVF₂. LLDPE-g-PMMA was demonstrated to be a good compatibilizer in LLDPE/PVF₂ blends, improving the interfacial adhesion and dispersion in the latter. Diffusion of PMMA side chains into PVF₂ in the interfacial region reduces the crystallization rate and lowers the melting point (T_m) and the crystallization temperature (T_c) of PVF₂ in the blends.     

Polymer blends containing poly(vinylidene fluoride). Part IV: Thermodynamic interpretations

A summary of the transitional behavior of blends containing poly(vinylidene fluoride), PVF₂, and various oxygen-containing polymers is presented. These data are used to establish the presence of a single miscible amorphous phase. The depression of the PVF₂ melting point in those blends judged to be miscible is analyzed using standard thermodynamic arguments to determine the heats of mixing between the amorphous diluents and the PVF₂. These heats of mixing are exothermic indicating the presence of strong interactions between the binary pairs. A comparison between the observed interaction strengths and the dipole moments of the various diluents suggests that the exothermic heats of mixing are the result of strong dipole-dipole interactions. Nearly all the miscible blends with PVF₂ show Lower Critical Solution Temperature (LCST) behavior. The direct correlation between the temperature location of this phase instability and the observed interaction strength suggests that the instability is more the result of enthalpic considerations than entropic ones.     

Morphological effects on glass transition behavior in selected immiscible blends of amorphous and semicrystalline polymers

The effects uncompatibilized immiscible polymer blend compositions on the T_g of the amorphous polymer were studied in the systems polystyrene/polypropylene (PS/PP), polystyrene/high density polyethylene (PS/PE) and polycarbonate/high density polyethylene (PC/PE). In the two similar systems of PS/PP and PS/PE, the T_g of PS increased with decreasing PS percentage in the blends. This variation in glass transition is attributed to the polymer domain interactions resulting from the different morphologies of various blend compositions. Experiments were conducted to study these effects by preparing blends with various polymers that varied the relationship between the T_g of the amorphous polymer and the crystallization behavior of the semicrystalline polymer. Results show that the variation in amorphous component T_g with composition depends strongly on the physical state of the semicrystalline domains. Whereas the T_g of PS in PS/PE blends changed with composition, the T_g of PC in the PC/PE blend did not change with composition.     

Adhesion of calcium phosphate coatings on polyethylene (PE), polystyrene (PS), poly(tetrafluoroethylene) (PTFE), poly(dimethylsiloxane) (PDMS) and poly-L-lactic acid (PLLA)

Calcium phosphate (CaP) coatings can be applied to improve the biological performance of polymeric medical implants. For clinical applications, a strong adhesion of the coating to the polymeric substrate is important. Therefore, the adhesion of rf magnetron-sputter-deposited CaP coatings on five polymers was studied: polyethylene (PE), polystyrene (PS), poly(tetrafluoroethylene) (PTFE), poly-L-lactic acid (PLLA) and poly(dimethylsiloxane) (PDMS). To influence the adhesion, the interface was varied in six different ways, e. g. by a plasma or ion-beam pretreatment, or by using a Ti interlayer. The adhesion was determined by using scratch, tensile and 180^° bend tests. Especially the polymers PE and PS needed a bombardment by energetic particles prior to or during coating deposition, to enable the formation of chemical bonds between the coating and the polymer, which gave adhesion. On PLLA and PDMS, being oxygen containing polymers, it was easier to establish a strong interface. An overtreatment of the polymeric substrates gave worse adhesion, probably due to the formation of weak low molecular weight (LMW) layers on the polymer. On PTFE, the use of a Ti interlayer was necessary to prevent the PTFE from UV degradation during coating deposition, as this caused cohesive failure within the PTFE. The results showed that each polymer requires a different approach for obtaining optimal adhesion. The observed adhesion could often be explained in the terms of processes occurred during the pretreatment of the polymers or the deposition of the coating.     

Triboelectrostatic separation of pvc materials from mixed plastics for waste plastic recycling

This study covers the triboelectrostatic separation of Polyvinylchloride (PVC) materials from mixed plastics such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and polystyrene (PS). The PVC material generates hazardous hydrogen chloride gas resulting from the combustion in the incinerators. The laboratory scale triboelectrostatic separation system consists of a fluidized-bed tribocharger, a separation chamber, a collection chamber and a controller. Negative and positive surface charges can be imparted to the PVC and PET particles, respectively, due to the difference of triboelectric charging series between the particles in the fluidized-bed tribocharger. They can be separated by passing through an external electric field. A highly concentrated PVC (91.9%) can be recovered with a yield of about 96.1% from the mixture of PVC and PET materials in a single stage of processing. For the removal of PVC from the two-component mixed plastics such as PVC/PET, PVC/PP, PVC/PE or PVC/PS, separation results show the recovery of 96–99% with the pure extract content in excess of 90%. The triboelectrostatic separation system using the fluidized-bed tribocharger shows the potential to be an effective method for removing PVC from mixed plastics for waste plastic recycling.     

Design and performance evaluation of multilayer packaging films for blister packaging applications

Five multilayer packaging film structures consisting of amorphous poly(ethylene terephthalate) (APET), low‐density polyethylene (LDPE), polypropylene (PP), and acrylonitrile/methyl acrylate copolymer (Barex) films [i.e., APET/polyethylene (PE), APET/PP, APET/PE + UV inhibitor, APET/PP/PE, and APET/Barex/PP] for blister packaging applications were designed and produced. Blister containers with APET/PE and APET/Barex/PP structures were prepared, and their optical, mechanical, barrier (O₂, CO₂, and H₂O), physical, and product/package compatibility performance properties were evaluated. Package/product compatibility with simulants (soy sauce and sunscreen skin cream) at 37.8°C was evaluated for 3, 7, 14, and 28 days in the multilayer films and the blister containers. APET/Barex/PP film showed significantly better O₂ and CO₂ barrier performance than the other four film structures. The UV inhibitor had no significant effect on the barrier properties in the APET/PE film structure. All of the film structures showed high enough elastic storage modulus values to be applied to blister packaging in a broad range of temperatures between ?45 and 80°C. The glass‐transition temperature of APET, which was responsible for the elastic modulus of the multilayer structure, decreased after the samples were exposed to the skin cream. This decrease may have been due to the sorption of the skin cream's active ingredients, such as ethylhexyl methoxycinnamate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Blends of the alternating ethylene–tetrafluoroethylene copolymer with poly(vinylidene fluoride)

Blends of the alternating ethylene–tetrafluoroethylene copolymer (ETFE) with poly(vinylidene fluoride) (PVF₂) were prepared by melt-mixing. Compatibility, morphology, thermal behavior, and mechanical properties of the ETFE/PVF₂ blends with various compositions were studied by using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), tensile tests, and scanning electron microscopy (SEM). DMA studies showed that the blends have separate glass transition temperatures (T_g) close to those of the pure polymers. ETFE and PVF₂ are incompatible. Marked negative deviations from simple additivity were observed for both the ultimate strength and the elongation at break over the entire composition range. The interfaces between ETFE and PVF₂ are weakly bonded with rather poor interaction. SEM observations revealed that the blends have a two-phase structure and the adhesion between the phases is poor. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:295–304, 1997     

Melting and crystallization behaviour of the poly(vinylidene fluoride)/poly(monobenzyl itaconate) blends

Summary Melting and crystallization behaviour of blends of poly(vinylidene fluoride)(PVF₂) and poly(monobenzyl itaconate) (PMBzI) have been analyzed as a function of the composition in the range 100-40% PVF₂. Using the Hoffman-Week plot we have not found an equilibrium melting point depression in all the blends studied. However, the addition of PMBzI to pure PVF₂ leads to an increase in its crystallization rate. The results suggest that both polymers are incompatible and that PMBzI acts as nucleating agent in the PVF₂ crystallization.     

Increase of photoluminescence from fullerene‐doped polymers under laser irradiation

Photoluminescence (PL) from fullerene (C₆₀ and C₇₀)‐doped polymers such as poly(methyl methacrylate) (PMMA), polystyrene (PS), poly(methyl phenyl silane) (PMPS) and poly(phenyl silsesquioxane) (PPSQ) increases gradually under laser irradiation in air (but not in vacuum and in nitrogen) and eventually becomes visible to the naked eye. Concomitantly, the PL peak is broadened and, in most cases, blue‐shifted. No such PL increases are observed for pure C₆₀ films made by vacuum vapor deposition and pure polymer films. Among the polymers used, fullerene‐doped PMMA has the greatest PL increase after several hours of laser irradiation and fullerene‐doped PMPS has the highest rate of PL increase at the initial stage of the laser irradiation. To gain an insight into the mechanism of the PL increase, laser‐irradiated fullerene‐doped PMMA samples were analyzed by UV‐Vis spectrophotometer, FT‐IR, mass spectrometry, GPC and NMR. The results show that the PL increase can be attributed to CH₆₀O_n‐polymer (or C₇₀O_n‐polymer) and oxidized fullerene‐polymer adducts formed by some laser‐induced photochemical reactions among fullerenes, oxygen and polymers.     

Inhibition of deterioration of plastics by hydroaromatics

Based on our previous works concluding that the addition of hydrogen-donating hydroaromatics is effective in inhibiting the deterioration of hydrocarbons, heavy hydroaromatics from petroleum (HHAP) that were produced by hydrogenating highly aromatic heavy oil containing partly hydrogenated condensed aromatic rings were examined by the addition to high-density polyethylene (PE), isotactic polypropylene (PP), and poly(vinyl chloride) (PVC, MW: 1300) after confirming its prominent hydrogen-donating ability. The following results were obtained by the deterioration tests and melt-flow tests: (1) Clear inhibiting effects could be found on preservation of elongation and tensile strength by the addition of 0.1% and 0.5% of HHAP to PE. (2) Cross-linking of PE was restricted by the addition of HHAP. (3) Obvious effects could be found on preservation of elongation and tensile strength by the addition of 0.5% of HHAP to PP, but 0.1% of HHAP was not so effective. (4) Melt-flow rate of PP at 270°C supported the results of the deterioration tests at 120°C. (5) Color changes were remarkably improved by the addition of HHAP to PVC (at 160°C, 140 min). From these results, hydrogen donation from hydroaromatics can be considered effective in inhibiting the deterioration of PE, PP, and PVC.     

Catalytic degradation and dechlorination of PVC-containing mixed plastics via Al-Mg composite oxide catalysts

A alumina-magnesium composite oxide catalyst (Al-Mg) was synthesized for catalytic degradation of poly vinyl chloride (PVC) containing polymer mixtures, i.e. polypropylene (PP)/PVC, low-density polyethylene (LDPE)/PVC, polystyrene (PS)/PVC, and LDPE/PP/PS/PVC. In the catalytic degradations the Al-Mg composite oxide catalyst accelerated the rate of polymer degradation and lowered the carbon distribution of liquid products. In addition, it showed good effect on the fixation of evolved HCl and greatly decreased the chlorine content in the oil. These results suggested that the Al-Mg composite oxide catalyst can be effectively used for catalytic degradation and dechlorination of PVC-containing mixed plastics.