Chlorinated polyethylene modification of blends derived from waste plastics. Part II: Mechanism of modification

Previous publications have shown that the stress-strain behavior, especially ductility, of some incompatible polymer blends are greatly improved by the addition of slurry produced chlorinated polyethylenes (CPE). This improvement is greatest for blends containing polyethylene and PVC. The most effective CPE's have some residual polyethylene crystallinity and may be described as block-like polymers with ethylene sequences and chlorine containing sequences. It is postulated that CPE addition improves the blend properties by increasing the adhesion between domains in the blend via interactions with the blend components. This hypothesis was explored by thermal analysis, dynamic mechanical testing, adhesion studies, and microscopy. It is concluded that the interaction of CPE with polyethylene derives from compatibility of rather long methylene sequences in CPE with the polyethylene which results in good adhesive bonding. The interaction of CPE with PVC may not be owing to segmental compatibility but simply good mutual adhesion between similar polar materials. There is no interaction or adhesion between CPE and polystyrene as would be expected. CPE addition to blends is accompanied by a decrease in component domain size. The relationship between CPE structure and its effectiveness as a blend modifier is discussed.     

Polystyrene-polyethylene melt blends obtained through reactive mixing process

Reactive polystyrene (OPS) and reactive polyethylene (CPE) with oxazoline and carboxylic acid functionality, respectively, were melt blended in a Rheomix mixer under a variety of conditions. The properties of these blends were examined and correlated with the compositions and mixing conditions such as shear rate, time, and temperature. An increase in torque was observed, which is believed related to chemical reaction between OPS and CPE. The difference between the maximum and minimum torque (T_max-T_min), increases from 48 to a maximum of 510 m-g for 10 and 40% CPE reacted blends, respectively, But on further increase in the CPE amount in the blend the torque increase drops reaching a final minimum value of 133 m-g for a blend with 90% CPE. Differential Scanning Calorimetry (DSC) studies reveal a single first order transition, due to CPE, for each of these polymer blends. Furthermore, evidence of the glass transition temperature for OPS diminishes with increasing CPE content and mixing time. Scanning Electron Micrographs (SEM) show a fine dispersion in these reactive blends, with particle size much smaller than a micron. Blends with 50% or more CPE have no distinguishable features as such. Mechanical properties such as elongation at break of reacted blends are improved over the nonreactive polyethylene (PE) and polystyrene (PS) blends. An intermolecular reaction between the OPS and CPE results in a graft polymer, which imparts improvement in the overall properties of these reacted blends. The maximum grafting reaction corresponds to 40% CPE blend, which is being evaluated as a potential compatibilizer.     

PVC/CPE/GF复合材料制备及力学性能

采用玻璃纤维(GF)及氯化聚乙烯(CPE)对聚氯乙烯(PVC)协同增韧改性.研究表明,当共混体系中有一定量的GF时,CPE的加入不仅能够改善共混物的韧性,还能够促进GF在PVC基体中的分散,两者协同增韧.随着CPE加入量的增加,GF分散效果增强,PVC/CPE/GF共混物的硬度呈现先显著增强后缓慢增强的趋势、拉伸强度和...     

PE-LD/PVDC/PE-LD复合薄膜回收料制备共混材料的研究

以废旧低密度聚乙烯/聚偏氯乙烯/低密度聚乙烯（PE-LD/PVDC/PE-LD）复合薄膜为基体材料,液体钙-锌(Ca-Zn)为热稳定剂,氯化聚乙烯(CPE)为相容剂,制备了PE-LD/PVDC/CPE共混材料,并对其热稳定性能、力学性能、阻透性能和微观形态结构进行了测试与分析。结果表明,加入1.2份液体Ca-Zn稳定剂,刚果红试纸起始变色温度和完全变色温度分别提高了8 ℃和11 ℃,刚果红试纸起始变色时间和完全变色时间分别延长了67 s和354 s,共混材料的热稳定性能大幅度提高;含4.5 %CPE的共混材料中,PVDC嵌入PE-LD中,相容性好,与未添加CPE的材料相比,其断裂伸长率提高了76.70 %,缺口冲击强度提高了30.01 %,吸油率下降了33.61 %,柔韧性和阻透性能明显提高。     

Thermal,morphological, and physicomechanical properties of (chlorinated polyethylene rubber)/(chloroprene rubber) blends

The effect of the blend ratio on the thermal, morphological, and physicomechanical properties of (chlorinated polyethylene rubber)/(chloroprene rubber) (CPE/CR) blends was studied. Two distinct glass transition temperatures (T_g) of all blends were observed in differential scanning calorimetry curves, falling between the T_g of the two pure rubbers. Analysis of the blends by scanning electron microscopy showed both dispersed and continuous phase morphology that depended on the blend composition. Thermogravimetric analysis showed that all the compounds underwent two stages of thermal degradation. The Mooney viscosity and optimum cure times increased with the increase in CPE contents, whereas the scorch times decreased. The tensile strength and elongation at break decreased, whereas the 100% modulus, hardness, and compression set increased with the increase of CPE content; the tear strength had the lowest value for the 50/50 CPE/CR blend because of the poor miscibility. The results from thermal aging and oil resistance tests showed that pure CPE possessed better thermal aging property and oil resistance than those of pure CR. Thus, considerable improvement in oil resistance of the blend compounds was achieved with the increase of CPE content. J. VINYL ADDIT. TECHNOL., 21:18–23, 2015. © 2014 Society of Plastics Engineers     

ABS/PVC/CPE共混体系的力学性能

研究了填充改性丙烯腈-丁二烯-苯乙烯(ABS)三元共聚物、聚氯乙烯(PVC)和CPE三元共混体系力学性能与结构的关系。结果表明，在ABS／PVC共混体系中加入增容剂氯化聚乙烯(CPE)后，提高了共混体系的相容性和机械力学性能；随着共混体系中CPE用量的增加，ABS／PVC／CPE共混体系的冲击强度、断裂伸长率上升，拉伸强度下降，而弹性模量则出现了极大值。     

Rheological properties,oil, and thermal resistance in sulfur‐cured CPE/NR blends

The use of natural rubber (NR) for partly substituting elastomeric chlorinated polyethylene (CPE) was carried out. Sulfur curing was used to vulcanize NR phase in the blends. Mechanical, rheological, and thermal aging properties as well as oil resistance of the blends were investigated. The amount of NR in blends significantly affects properties of the blends. With NR content in blends up to 20 wt %, tensile properties are similar to those of the pure CPE, even after either oil immersion or thermal aging. Rheological properties of CPE/NR blends determined from the rubber process analyzer (RPA 2000) and parallel‐plate rheometer are controlled strongly by the blend composition. The viscoelastic behavior of pure CPE and the blends with CPE as a major component is governed by the viscous response, which could be seen from the high damping factor, particularly at high strain, the short linear viscoelastic range, and the high degree of pseudoplasticity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1129–1135, 2004     

Mechanical properties of polypropylene-low density polyethylene blends

Blends of polypropylene (PP) and low density polyethylene (LDPE) were prepared by both batch mixing followed by compression molding and extruder compounding followed by injection molding. Compression molded PP-LDPE blends were found to have very poor toughness, whereas extruded blends, injection molded without weld lines, were quite tough. Injection molded blend specimens with weld lines were found to be weaker and failed at very low elongations at break. A simple adhesion analysis is presented which explains well the weakness at the weld line expected for incompatible blends. Addition of an ethylene-propylene polymer with residual ethylene crystallinity was found to be a more effective “compatibilizer” for blends deficient in toughness than a related copolymer with less crystallinity. This effect is attributed to the more block-like character of the former which permits it to play more nearly the interfacial role required of the ideal blend compatibilizing agent.     

Compatibilizers for recycling of the plastic mixture wastes. II. The effect of a compatibilizer for binary blends on the properties of ternary blends

In this article, we discuss the effect of a compatibilizer for binary blends on the properties of ternary blends composed of high‐density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) and poly(vinyl chloride) (PVC) virgin polymers with a simulated waste plastics fraction. Chlorinated polyethylene (CPE), ethylene–propylene rubber (EPR), and their 1/1 (w/w) mixture were tested as compatibilizers for the HDPE/PP/PVC ternary blend. CPE, styrene‐ethylene‐propylene block copolymer (SEP), or their 1/1 (w/w) mixture were tested as compatibilizers for the HDPE/PS/PVC ternary blend. The composition of the ternary blends were fixed at 8/1/1 by weight ratio. The amount of the compatibilizer was 3 phr. Rheological, mechanical, and thermal properties were measured. For the 8/1/1 HDPE/PP/PVC ternary blends, the tensile strength was slightly decreased, but the impact strength was significantly increased by adding EPR, CPE, or their mixture. EPR exhibited the most significant impact modification effect for the ternary blends. In a similar way, for 8/1/1 HDPE/PS/PVC ternary blends, on adding SEP, CPE, or their mixture, the tensile strength was slightly decreased, but the impact strength was noticeably increased. It was found that the SEP worked much better as an impact modifier for the ternary blends than CPE or the SEP/CPE mixture did. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1048–1053, 2000     

Blends of high‐density polyethylene with chlorinated polyethylene: Morphology,thermal, rheological,and mechanical properties

Blends of high‐density polyethylene (HDPE) with chlorinated polyethylene (CPE) were generated using melt mixing. CPE of two different chlorination contents was used and its amount in the blends was varied from 1% till 30%. The rheological, thermal, mechanical, and morphological properties of the blends were characterized along with miscibility analysis. In general, better mixing of the CPE polymer in HDPE was observed at lower CPE concentration and reduced mixing or immiscibility occurred at higher concentration of CPE. However, the extent of immiscibility was different in both CPE25 and CPE35 systems. The rheological analysis of the data using Cole‐Cole, Han‐Chuang and van Gurp plots confirmed the miscibility of CPE25 blends (except for 30% CPE25 blend at lower frequency) whereas CPE35 blends with 10–30% CPE content were immiscible. Highest increase in the rheological properties (complex moduli) was observed at 2% CPE content. The mechanical properties of the CPE25 blends were superior than the corresponding CPE35 blends especially at higher CPE concentration where effects of immiscibility as well as matrix plasticization played a role. The morphology characterization using TEM indicated change in the crystalline features of the polymer in the case of CPE35 blends. The optical microscopy also confirmed the better mixing of CPE25 polymers in HDPE than CPE35. The CPE25 blends exhibited uniformly dispersed CPE phase which was also confirmed by the rheological analysis. However, the blends of CPE35 with 10% CPE content onwards had significant phase immiscibility. POLYM. ENG. SCI., 54:85–95, 2014. © 2013 Society of Plastics Engineers     

Application of phase dispersion–crosslinking synergism on recycling commingled plastic wastes

A tetra‐component blend, consisting of low‐density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS), was studied as a model system of commingled plastic wastes (LDPE/PVC/PP/PS, mass ratio: 70/10/10/10). Effects of chlorinated polyethylene (CPE), ethylene–propylene–diene monomer (EPDM), styrene–butadiene–styrene (SBS), and their mixture (CPE/EPDM/SBS, mass ratio: 2/2/2) on the mechanical properties and morphology of the system were investigated. With addition of several elastomers and their mixture, the tensile strength of the blends decreased slightly, although both the elongation at break and the impact strength increased. Among these elastomers, EPDM exhibited the most significant impact modification effect for the tetra‐component blends. SBS and the mixture have a good phase‐dispersion effect for the tetra‐component blend. By adding a crosslinking agent [dicumyl peroxide (DCP)], the mechanical properties of the tetra‐component blends also increased. When either SBS or the mixture was added to the blend together with DCP, the probability that the crosslinking agent (DCP) would be at the interface improved because of the phase‐dispersion effect of SBS. Therefore, more co‐crosslinked products will form between LDPE and other components. Accordingly, remarkable improvement of the interfacial adhesion and hence the mechanical properties of the tetra‐component blends occurred. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2947–2952, 2001     

A Study of the Viscoelastic and Rheological Properties of PVC/CPE Blends Modified by Using Polylauryllactam

Abstract

Polylauryllactam was used to improve the impact strength of polyvinylchloride (PVC)/chlorinated polyethylene (CPE) blends without sacrificing their tensile properties. The enhancement of the impact strength increased with the increase of the CPE content in the PVC/CPE blends due to the formation of intermolecular hydrogen bonds among PVC, polylauryllactam and CPE macromolecules. A doubled impact strength of the PVC/CPE blend with 20 weight percent of CPE was obtained after the addition of 1.5 phr polylauryllactam. The PVC/CPE blends with polylauryllactam have a better dimensional stability compared with the PVC/CPE blends without the additive, according to their viscoelastic characteristics. Polylauryllactam shortened the processing time to reach a minimum melt viscosity in the processing of the PVC/CPE blends.     

High performance LDPE/thermoplastic starch blends: a sustainable alternative to pure polyethylene

Thermoplastic starch (TPS), as opposed to dry starch, is capable of flow and hence when mixed with other synthetic polymers can behave in a manner similar to conventional polymer-polymer blends. This paper presents an approach to preparing polyethylene/thermoplastic starch blends with unique properties. A one-step combined twin-screw/single screw extrusion setup is used to carry out the melt-melt mixing of the components. Glycerol is used as the starch plasticizer and its content in the TPS is varied from 29 to 40%.Under the particular one-step processing conditions used it is possible to develop continuous TPS (highly interconnected) and co-continuous polymer/TPS blend extruded ribbon which possess a high elongation at break, modulus and strength in the machine direction. The PE/TPS (55:45) blend prepared with TPS containing 36% glycerol maintains 94% of the elongation at break and 76% of the modulus of polyethylene. At a composition level of 71:29 PE/TPS for the same glycerol content, the blend retains 96% of the elongation at break and 100% of the modulus of polyethylene. These excellent properties are achieved in the absence of any interfacial modifier and despite the high levels of immiscibility in the polar-nonpolar TPS-PE system. The 55:45 blend possesses a 100% continuous or fully interconnected TPS morphology, as measured by hydrolytic extraction. This highly continuous TPS configuration within the blend should enhance its potential for environmental biodegradation. The elongation at break in the cross direction of these materials, although lower than the machine direction properties, also demonstrates ductility at high TPS concentrations. At a glycerol content of 36% in the TPS, the blends demonstrate only very low levels of sensitivity to moisture. A high degree of transparency is maintained over the entire concentration range due to the similar refractive indices of PE and TPS and the virtual absence of interfacial microvoiding.Effective control of the glycerol content, TPS concentration and processing conditions can result in a wide variety of morphological structures including spherical, fiber-like, highly continuous and co-continuous morphologies. These various blend morphologies are shown to be the determining parameters with respect to the observed mechanical properties.This material has the added benefit of containing large quantities of a renewable resource and hence represents a more sustainable alternative to pure synthetic polymers.     

高透低摩擦CPE薄膜的制备及性能研究

采用三层共混挤出流延工艺,以聚乙烯树脂为原料,添加开口爽滑双功能母粒(PE-014S)制备高透低摩擦流延聚乙烯(CPE)薄膜。通过对薄膜光学性能、力学性能及摩擦性能测试,当PE-014S添加量为3份时,CPE薄膜透光率为92.8%,雾度为1.5%,光泽度为93.2 GU,纵向拉伸强度为21.3 MPa,横向拉伸强度为20.6 MPa,纵向断裂伸长率为1586.1%,横向断裂伸长率为1497.8%,静摩擦系数为0.23,动摩擦系数为0.14,表明PE-014S双功能母粒具有异相成核作用、增透作用及增强增韧功能;对PE/PE-014S共混物进行流变性能测试,结果表明PE-014S具有良好的加工性能;对CPE薄膜截面微观结构观察,发现PE-014S与PE树脂具有较好的界面融合性,均匀分散于聚乙烯中,形成一定的凸起结构。综合来看,添加PE-014S可提高CPE薄膜各项性能,为高透低摩擦CPE薄膜的生产制备提供技术支撑。     

Stress–strain behavior of polyolefin blends

As part of a study on reuse of plastics as blends, the yield tensile strength, elongation at break, and the modulus of melt blends of low-density polyethylene, high-density polyethylene, and polypropylene have been studied over the entire ternary composition range. The modulus and strength are nearly monotonic functions of blend composition. The contribution of the pure components to these properties is roughly additive. The elongation at break is a more complex function of composition in that minima are observed near the center of the triangular composition diagram and on each of the three binary legs. The response is nearly symmetrical along two of the binary legs but is skewed toward high-density polyethylene for blends of high- and low-density polyethylene. The deterioration of elongation produced by blending is much less severe for polyolefins than observed for other blend systems. This, combined with the observed additivity of strength, make polyolefin blends mechanically superior to blends of other plastics found in wastes. This fact is interpreted in terms of compatibility and amorphous phase interactions which are likely for polyolefins. Modification of polyolefin blends by addition of a rubbery copolymer of ethylene and propylene produced large improvements in elongation at break for some compositions.     

弹性体在车用仪表板表皮材料中的应用

利用DSC和SEM等方法研究了弹性体在汽车仪表板表皮材料用PVC/ABS软质合金中的作用。结果表明,在PVC/ABS共混体系中加入弹性体CPE、NBR后,有助于提高共混体系的相容性,从而使得PVC/ABS共混体系的机械强度和加工性能也发生变化。     

Property–composition dependence of isotactic poly(butene-1)-chlorinated polyethylene blends

Melt-mixed blends of isotactic poly(butene-1) (PB) with chlorinated polyethylene (containing 48 wt % Cl) (CPE) were studied in the complete composition range. Phase contrast, polarizing, and scanning electron microscopy revealed that the blend is heterogeneous. The results were confirmed by the dynamic mechanical technique and differential scanning calorimetry. The latter technique indicated also that CPE does not influence the crystallinity of PB. Tensile behavior of the blends was good, especially at low CPE contents. The results were analyzed using phenomenological mechanics models. From the correlation obtained one can conclude that the blends are mechanically compatible. Limiting oxygen index data were also determined, to characterize the flammability behavior of the blends in the complete composition range.     

Translucent blends of chlorinated polyethylene with poly(vinyl chloride)

Some experimental chlorinated polyethylene (CPE) resins that produced translucent blends with PVC were used to study the effects of CPE chlorine content and chlorine distribution on the morphology, optical clarity, and toughness of blends with PVC. The CPE resins were characterized in terms of the glass transition temperature, residual crystallinity, density, and refractive index. Increasing residual crystallinity and increasing chlorine content both increased the refractive index closer to that of PVC. A linear relationship was observed between the fourth power of the refractive index and the CPE glass transition temperature. With a phase-separated blend morphology in all cases, improved transparency was achieved in this system by reducing the refractive index difference between CPE and PVC. Both haze and transparency showed the predicted linear dependence on the square of the refractive index difference. To a first approximation, modifications of the experimental CPE resins that improved optical transparency of the blends also tended to reduce the toughness enhancement.     

红泥和废油渣在CPE及并用材料中的应用

分别以CPE,CPE/VPB及CPE/PVC为基材,以红泥为填料,石油炼厂废油渣为增塑剂和软化剂,讨论了废油渣的增塑软化作用,红泥的填充效果,及增塑和填充后CPE,CPE/VPB和CPE/PVC系列卷材的力学性能,热氧及臭氧稳定性等。结果表明,红泥/废油渣/CPE和红泥/废油渣/CPE/VPB两体系均具有制备系列卷材所适宜的力学性能和良好的耐臭老化和热氧老化性能。选用CPE 100,废油渣35,红泥200,其拉伸强度为12MPa,扯断伸长率为300％,邵A硬度为90。选用CPE/VPB=75/25,废油渣为35,红泥150,其拉伸强度为7.5MPa,扯断伸长率为500％,邵A硬度为65,而废油渣/红泥/PVC/CPE共混体系虽强度较高,但伸长率较低。     

Morphology evolution of immiscible LDPE/PVC blends in the presence of compatibilizer and phase dispersant

Phase dispersion and coalescence in low‐density polyethylene (LDPE)/polyvinyl chloride (PVC) (70/30) blends influenced by compatibilizer and phase dispersant was studied. It was found that the morphology evolution of blends is sensitive to not only processing conditions (shear strength and mixing time) but also the added compatibilizer or phase dispersant. In our conditions, the stable phase morphology of each blend is obtained after mixing 15–25 min. In addition, the dispersed PVC phase in blends is easy to aggregate when the mixing rotor speed changed from high to low for the binary blends. As a compatibilizer, chlorided polyethylene (CPE) or nitrile rubber (NBR) can stabilize the morphology and hinder the coalescence of the dispersed PVC phase when added to the blends. However, the phase dispersant butadiene rubber (BR) or styrene butadiene rubber (SBR) could not stabilize the phase structure, although it could accelerate phase dispersion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 763–772, 2004