Compatibility of recycled PVC/ABS blends. Effect of previous degradation

The aim of the present study is to analyze the compatibility between recycled poly(vinyl chloride) (PVC) and acrylonitrile butadiene styrene (ABS). With this objective, blends made from recycled PVC obtained from credit cards and both virgin ABS and recycled ABS obtained from the electrical and electronic sector were prepared, and the range of compositions from 0 to 100 wt% were analyzed. The level of degradation existing within the recycled materials was analyzed using the Fourier transform infrared spectroscopy and thermogravimetric analysis. The existence of partial compatibility between the components of the blend was determined using differential scanning calorimetry. The presence of the elastomeric phase in the ABS is a significant factor which needs to be taken into account when studying the phenomena of interfacial adhesion. In addition, dynamic mechanical analysis has been used to analyze the effect of temperature upon stiffness, in the function of the composition of the blend. The tensile strength of the blends has been adjusted according to the equivalent box model, which has allowed the determination of the level of adhesion at the interface of the blend components. Finally, a morphological study of the fracture has been completed using scanning electron microscopy. POLYM. ENG. SCI., 47:789–796, 2007. © 2007 Society of Plastics Engineers     

Mechanical properties of recycled PVC blends with styrenic polymers

The aim of this study is to improve the performance of blends made from recycled polyvinyl chloride (PVC), coming from credit card waste, so that these blends can be used for those applications that must fulfil some requirements with regard to mechanical properties and stability with temperature alterations. With this aim in mind, two polymers of styrenic origin have been combined: styrene acrylonitrile (SAN) and acrylonitrile butadiene styrene (ABS). These polymers are characterized by a satisfactory balance of mechanical properties and thermal stability. PVC blends with both virgin and recycled styrenic polymers have been studied throughout the entire range of compositions. The prior degradation of the recycled materials has been studied by means of Fourier transformed infrared spectroscopy (FTIR).The behavior of the observed T_g values has been analyzed using differential scanning calorimetry (DSC), and the existence of partial miscibility between the different components has been studied. The mechanical properties have been determined using tensile and Charpy impact tests. The thermal stability of the PVC blends with temperature changes has been determined using the Vicat softening temperature (VST). Finally, the fracture surface of the various blends has been analyzed using scanning electron microscopy (SEM). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2464–2471, 2006     

Miscibility and rheological properties of poly(vinyl chloride)/styrene–acrylonitrile blends prepared by melt extrusion

Styrene–acrylonitrile (SAN) with acrylonitrile (AN) concentrations of 11.6–26 wt % and α‐methylstyrene acrylonitrile (αMSAN) with a wide range of AN concentrations are miscible with poly(vinyl chloride) (PVC) through solution blending. Here we examine the rheological properties and miscibility of PVC/SAN and PVC/αMSAN blends prepared by melt extrusion for commercial applications. We have investigated the rheological properties of the blends with a rheometer and a melt indexer. The PVC/SAN and PVC/αMSAN blends have a low melting torque, a long degradation time, and a high melt index, and this means that they have better processability than pure PVC. The miscibility of the blends has been characterized with differential scanning calorimetry, dynamic mechanical thermal analysis, and advanced rheometrics expansion system analysis. The miscibility of the blends has also been characterized with scanning electron microscopy. The SAN series with AN concentrations of 24–31 wt % is immiscible with PVC by melt extrusion, whereas αMSAN with 31 wt % AN is miscible with PVC, even when they are blended by melt extrusion, because of the strong interaction between PVC and αMSAN. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

One step forward to a sustainable green solution for extruded foam PVC building products

This paper is dedicated to the development of a robust and cost‐effective formulation to maximize the use of recycled poly(vinyl chloride) (PVC) back into its virgin compounds. This study concludes that a balanced stabilizer and lubricant formulation will overcome the detrimental effects of repeated heat history on the recycled/regrind PVC. The developed formulation using up to 70% of recycled/regrind PVC has been successfully implemented in the extrusion process for manufacturing high‐quality foam PVC profiles for the building industry. As a result, this study takes a huge step forward toward a green and sustainable solution for PVC applications. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Processability,rheology, and thermal,mechanical, and morphological properties of postconsumer poly(vinyl chloride) bottles and cables

The processability, rheology, and thermal, mechanical, and morphological properties of three different commercial poly(vinyl chloride) (PVC) compounds blended with postconsumer PVC bottles and PVC cables were examined with respect to the recycled PVC content. The addition of PVC bottle recyclates [recycled bottles (RBs)] into virgin PVC bottle (VB) and virgin PVC pipe (VP) compounds caused a progressive reduction in the average torque. No thermal degradation or color change in the RB‐blended PVC compounds used was detected through carbonyl and polyene indices from IR analysis. The rheological properties for VP compounds were more sensitive to RB addition than those of VB compounds. The extrudate swell ratio did not change with the RB content. The decomposition temperature for the VB and VP compounds increased at 60–80% RB, whereas the glass‐transition temperature was unaffected by the RB loading. The 20 and 80 wt % RB loadings were recommended for the VB and VP compounds, respectively, for the optimum impact strength, the blends showing ductile fracture with a continuous phase. At the optimum impact and tensile properties, introducing RB recyclates into the VB compounds gave better results than the VP compounds. The hardness and density of the VB and VP compounds did not change with the RB content. The RB property change was comparatively faster than that of recycled PVC pipes. Adding the PVC cable recyclate [recycled cable (RC)] to virgin PVC cable (VC) had no obvious effect on the torque value of the RC/VC blends. The decomposition temperatures of the RC/VC blends stabilized at 20–60% RC and tended to decrease at 80% RC. The ultimate tensile stress was improved by the addition of the RC compounds, whereas the hardness and density of the VC compounds were unaffected by the RC content. It was concluded that the optimum concentrations of PVC recyclates to be added to virgin PVC compounds were different from one property to another and also depended on the type of virgin PVC grade used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2738–2748, 2003     

Processing and mechanical properties of recycled PVC and of homopolymer blends with virgin PVC

Mechanical and processing properties of recycled polyvinylchloride (PVC, from bottles and pipes) were compared with those of virgin pipe grade PVC. Blends of recycled and pipe grade PVC were also prepared and characterized. It was found that the particle size and the restabilization of the recycled PVC are the two main points to be considered for obtaining virgin/recycled PVC blends with uniform and good mechanical properties. In general, recycled PVC not only does not significantly reduce the modulus and tensile strength, but also improves the impact strength and processing behavior of pipe grade virgin PVC. Only the thermomechanical resistance is slightly lowered. The latter points hold, of course, only when the recycled PVC contains both reinforcing and modifier agents. © 1996 John Wiley & Sons, Inc.     

Effect of dehydrochlorination of PVC on miscibility and phase separation of binary and ternary blends of poly(vinyl chloride), poly(ethylene-co-vinyl acetate) and poly(styrene-co-acrylonitrile)

The enhancement of miscibility at the lower critical solution temperature (LCST) of the blends poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) (PVC/EVA), poly(vinyl chloride)/poly(styrene-co-acrylonitrile) (PVC/SAN) and poly(vinyl chloride)/poly(ethylene-co-vinyl acetate)/poly(styrene-co-acrylonitrile) (PVC/EVA/SAN) was observed at the micron level. Such miscibility is attributed to the dehydrochlorination and formation of hydrogen bonds between blend components. However, macrolevel immiscibility of these blends heated to the LCST was observed. Such microdomain compatibility of these blends gives a synergistic character. Brittle-type failure observed for LCST samples testifies to the synergism in treated blends. ©1997 SCI     

Compatibility of poly(ϵ-caprolactone) (PCL) and poly(styrene-co-acrylonitrile) (SAN) blends. II. The influence of the AN content in SAN copolymer upon blend compatibility

The compatibility of polymer blends of poly(?-caprolactone) (PCL) and poly(styrene-co-acrylonitrile) (SAN) containing various acrylonitrile (AN) contents was studied to evaluate the influences of copolymer composition and PCL concentration upon blend compatibility. Blend compatibility was characterized by the occurence of a single glass transition intermediate between the transitions of the respective pure components. The glass transitions were determined by differential scanning calorimetry (DSC) and dynamic mechanical measurement (Rheovibron). It was found that SAN and PCL form compatible blends when the AN content of SAN ranges from 8% to 28% by weight. These blends are compatible in all proportions except for SAN 28 (AN wt % = 28) and PCL blends containing 70 or 85 wt % PCL. Blends of PCL and SAN were found to be incompatible when the AN content in SAN is greater than 30 wt % or less than 6 wt %. Lower critical solution temperature (LCST) behavior, which can be attributed to phase separation, was found to occur when these blends were heated to elevated temperatures. The cloud point, or phase separation, was found to vary with AN content in SAN and the concentration of SAN in the blend.     

Phase equilibrium in the binary and ternary blend system: Polycaprolactone-polyvinyl chloride-styrene acrylonitrile copolymer

An experimental study of binary and ternary phase equilibrium in the system polycaprolactone (PCL) poly(vi-nylchloride) (PVC)-77/23 styrene-acrylonitrile copolymer (SAN) is described. Miscibility is determined using differential scanning calorimetry (DSC) and turbidity. PCL/PVC and PCL/SAN are largely miscible systems but PVC/SAN is immiscible. The ternary system shows considerable miscibility. The blends are characterized by polarized light microscopy and wide-angle X-ray diffraction. The former measurement characterizes the structure of the spherulites. Additions of PVC, SAN, or PVC/SAN causes the spherulites observed in PCL to grow in size and become coarse. X-ray diffraction shows no movement of crystallographic peaks indicating the crystallographic unit cell is composed of PCL. Melting point depression measurements are used to calculate Flory χ interaction parameters for PCL/PVC and PCL/SAN. The melting point depression is also considered and used to investigate PVC/SAN interaction. An effort is made to compute the ternary phase diagram and tie lines.     

Mechanical Properties and Morphology of Recycled. Plastic Wastes by Solution Blending

In this study, bottles of mineral water and yogurt as well as Styrofoam bowls were recycled and identified by infrared spectroscopy as poly(vinyl chloride) (PVC), high-impact polystyrene (HIPS), and polystyrene (PS). Solution blending was employed to make polymer blends from these recycled plastics, including PVC/PS, PVC/HIPS/PS blends, and PVC/HIPS blends with or without a com-patibilizer, styrenelp-chlorostyrene (ST-CMS). Thermal behavior from differential scanning calorimetry was used to examine the compatibility of the blends. For the PVC/PS and PVC/HIPS/PS systems, it is found that although the third component (HIPS) may not be good enough as a compatibilizer, the addition of HIPS to the two-component blend (PVC/PS) may enhance the mechanical properties at the specific composition, especially for the blends at the intermediate concentrations. For PVC/HIPS blends with the ST-CMS copolymer as a compatibilizer, all the mechanical properties of the blends except the elongation at break, in general, increased with increasing the concentration of compatibilizer due to the increase of compatibility. The abnormal fracture strain was attributed to the differences in adhesion when various amounts of ST-CMS was added. The results of mechanical properties of the blends were consistent with the morphology from scanning electron microscopy.     

Recycled milk pouch and virgin LDPE‐LLDPE‐based jute fiber composites

The present investigation deals with the thermo‐mechanical recycling of post consumer milk pouches (LDPE‐LLDPE blend) and its use as jute fiber composite materials for engineering applications. The mechanical, thermal, morphological, and dynamic‐mechanical properties of recycled milk pouch‐based jute fiber composites with different fiber contents were evaluated and compared with those of the virgin LDPE‐LLDPE/jute fiber composites. Effect of artificial weathering on mechanical properties of different formulated composites was determined. The recycled polymer‐based jute fiber composites showed inferior mechanical properties as well as poor thermal stability compared to those observed for virgin polymer/jute fiber composites. However, the jute‐composites made with (50:50) recycled milk pouch‐virgin LDPE‐LLDPE blend as polymer matrix indicated significantly superior properties in comparison to the recycled milk pouch/jute composites. Overall mechanical performances of the recycled and virgin polymeric composites were correlated by scanning electron microscopy (SEM). The dynamic mechanical analysis showed that storage modulus values were lower for recycled LDPE‐LLDPE/jute composites compared to virgin LDPE‐LLDPE/jute composites throughout the entire temperature range, but an increase in the storage modulus was observed for recycled‐virgin LDPE‐LLDPE/jute composites. POLYM. COMPOS. 28:78–88, 2007. © 2007 Society of Plastics Engineers     

Fourier transform infrared spectroscopy in the study of the interaction between PVC and plasticizers: PVC/plasticizer compatibility

The interactions between Poly(vinyl chloride) (PVC) and Plasticizers, responsible for polymer plasticization, can be detected by means of Fourier transform infrared spectroscopy (FTIR). The interaction capacity between the two components depends on plasticizer chemical nature, PVC stereoregularity, and plasticizer content. In the case of ternary systems, consisting in PVC and two different plasticizers, their interaction with PVC depends essentially on their chemical nature. In this work, FTIR spectroscopy is applied to determine the effect of the cited factors on the compatibility between plasticizer and resin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

On a contribution to study some mechanical properties of WEEE recycled polymer blends

This research deals with the study of acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC) totally derived from wastes of electrical and electronic equipment (WEEE). The aim of this study is to investigate the macroscopic use properties of 100% recycled polymers and compare them with the virgin materials. First, a preliminary work of sorting and characterization of the wastes was necessary to identify the predominant polymer components in the lots. Then, four compositions of blends (ABS/PC) were performed at laboratory using the twin-screw extruder and injection techniques. Next, a series of experimental tests were carried out to investigate the morphology of the blends, their mechanical and thermo-mechanical behavior. The experimental results highlighted the synergistic effect by blending ABS and PC wastes. In addition, the comparison with the virgin mixtures has shown a decrease in the mechanical properties of the waste blends, however, the mechanical behavior is still ductile and the blends stiffness was enhanced.     

Recycling of poly(ethylene terephthalate) into closed‐cell foams

The increase of the elongational viscosity of recycled poly(ethylene terephthalate) (PET) is investigated with the aim of producing closed‐cell foams by means of a cost‐effective reactive extrusion technique. A recycled PET grade containing controlled contamination levels of polyvinyl chloride (PVC) and poylethylene (PE) is selected, and compared with virgin bottle‐grade PET as a reference. Reactive processing with a tetrafunctional epoxy additive induces randomly branched molecules with a lower degree of branching in recycled PET than in virgin PET, as shown by a molecular structure analysis. The corresponding increase in elongational viscosity is related to foaming experiments performed using supercritical CO₂ in a pressurized vessel. Observations of foam microstructures reveal that modified virgin PET forms closed‐cell structures under a large variety of foaming conditions, as opposed to unmodified virgin and recycled PET, which collapse as a result of insufficient elongational resistance. Closed‐cell foams are also obtained using modified recycled PET, providing that the temperature at which the pressure is released is lowered to 260°. Recycling of PET into closed‐cell foams is thus achieved, although the processing window is slightly reduced compared to virgin PET.     

Influence of additional thermal stabilizers on the reprocessing of postconsumer poly(vinyl chloride) bottles

The addition of heat stabilizers is essential for preventing the degradation of poly(vinyl chloride) (PVC) during its processing. The heat stabilizers consumed in the first run have to be made up before the reprocessing of recycled PVC. In this study, solvent‐cast films, which were prepared from granulated postconsumer PVC bottles mixed with plasticizers and thermal stabilizers, were used. The films were subjected to various heat treatments. No considerable structural change upon heat treatments at 140–160°C was found in IR and differential scanning calorimetry analyses. Polyene formation observed through ultraviolet analysis was not severe, indicating that the added stabilizers worked well in preventing degradation. The weight loss during the heat treatments was attributed partly to the decomposition of PVC and the evaporation of volatile components and mainly to the removal of the solvent upon heating. Although this study was conducted with water bottles that were to be recycled, it may be equally well applied to other similarly formulated PVC‐based materials, such as packaging films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3994–3999, 2003     

Compatibility and biodegradability of blendsof starch cinnamate with various polymers

The compatibility of blends of starch cinnamate (StCn) with polyvinyl chloride (PVC), polystyrene (PS), and styrene acrylonitrile copolymer (SAN) has been examined through viscometry at 30°C. The results of the three systems are compared with the already reported PMMA/StCn system. From the intrinsic viscosity, relative viscosity, reduced viscosity, and density measurements the PVC/StCn and SAN/StCn blends were found to be compatible while PS/StCn blend was found to be incompatible. The compatibility of the blends was also confirmed by SEM analysis. The compatibility of these blends based on heat of mixing and polymer-polymer interaction parameter was also examined. Blends were observed to be compatible on the basis of heat of mixing theory but not on the basis of polymer - polymer interaction parameters. Biodegradation studies of compatible blends containing 30% StCn showed 13%, 15%, 18%, and 23% weight loss in case of PMMA, SAN, and PVC blends after 120 days.     

乙烯-甲基丙烯酸甲酯共聚物增容回收聚乙烯／聚氯乙烯共混体系的研究

采用乙烯-甲基丙烯酸甲酯共聚物（EMMA）作为增容剂制备了回收聚乙烯／聚氯乙烯（RPE／PVC）共混材料。通过差示扫描量热仪（DSC）研究了共混材料两相之间的相容性;通过微控电子万能实验机、电子冲击实验机研究了EMMA和RPE对共混材料性能的影响。DSC试验结果表明,EMMA能显著改善PVC与RPE之间的相容性,使共混材料中PVC的玻璃化转变峰变宽且变得模糊;力学性能试验结果表明,加入3份EMMA时,RPE／PVC（10／100）共混材料的冲击强度、拉伸强度、弯曲强度和弯曲模量分别提高了270％、74％、60．9％和9．1％;随着RPE含量的增加RPE／PVC共混材料的力学性能下降,当EMMA含量为3份、RPE含量为10份时,共混材料的综合性能较佳。     

Miscibility studies of polymer blends by viscometry methods

The intrinsic viscosities of blends of poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) (PVC/EVA), poly(vinyl chloride)/poly(styrene-co-acrylonitrile) (PVC/SAN), and poly(ethylene-co-vinyl acetate)/poly(styrene-co-acrylonitrile) (EVA/SAN) have been studied in cyclohexanone as a function of blend composition. In order to predict the compatibility of polymer pairs in solution, the interaction parameter term, Δb, obtained from the modified Krigbaum and Wall theory, and the difference in the intrinsic viscosities of the polymer mixtures and the weight average intrinsic viscosities of the two polymer solutions taken separately are used. © 1994 John Wiley & Sons, Inc.     

Effect of compatibilizer on morphology and mechanical properties of TPU/SAN blends

Melt blends of thermoplastic polyurethane (TPU) and Poly(styrene‐co‐acrylonitrile), (SAN) of various compositions were prepared using a two‐roll mill. Two blends of composition 70:30 and 50:50 TPU/SAN were selected for compatibility studies. The compatibility effect of SMA on these incompatible blends was studied. The morphology and physical properties of blends were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectra (FTIR) and mechanical properties. TPU/SAN/SMA 70:30:5 showed better compatibility than other blend ratios.     

乙烯-甲基丙烯酸甲酯共聚物对聚氯乙烯／聚丙烯复合材料性能的影响

以乙烯-甲基丙烯酸甲酯共聚物（EMMA）为增容剂制备了聚氯乙烯（PVC）／聚丙烯（PP）复合材料．采用DSC表征了复合材料的相容性,用WDW3020微控电子万能实验机、XCJ-40电子冲击实验机测试了复合材料的力学性能;并与氯化聚乙烯（CPE）增容PVC／PP共混体系进行了比较。试验结果表明：EMMA能显著改善PVC与PP的相容性。当增容剂用量为9份时,与未增容PVC／PP体系相比。缺口冲击强度,拉伸强度和弯曲强度分别提高了191％,70％,41％;与CPE增容PVC／PP体系相比,缺口冲击强度,拉伸强度和弯曲强度分别提高了44％,39％,12％。