Experimental investigation of the morphology development and mechanical properties of waste ethylene propylene diene monomer/polypropylene blend in modular intermeshing corotating twin‐screw extruder

Nowadays, with the increase in the number of automobiles, waste EPDM (ethylene propylene diene monomer) is causing a significant environmental problem. From environmental and economical perspectives, recycling is one of the popular methods to solve environmental problems. This study, which involved waste EPDM/PP (polypropylene) blends with the ratio range of 70/30 and 75/25, set out to ascertain the relevance of the mass percentage of the dispersed phase, the influence of the screw geometry, the screw rpm, and the melting temperature of PP materials on the morphology and mechanical properties of the waste rubber blend. The purpose of this study is to develop a high‐value thermoplastic elastomer from waste EPDM. This investigation concentrated on determining the optimum conditions for producing a blend by extrusion, relative to screw geometry, screw rational speed, and operating temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2276–2282, 2002     

Effect of ultrasound on extrusion of polypropylene/ethylene–propylene–diene terpolymer blend: Processing and mechanical properties

The effects of ultrasonic irradiation on extrusion processing and mechanical properties of polypropylene (PP)/ethylene–propylene–diene terpolymer (EPDM) blends are examined. Results show that appropriate irradiation intensity can prominently decrease die pressure and apparent viscosity of the melt, increase output, as well as increase toughness of PP/EPDM blends without harming rigidity. In case the blends are extruded with ultrasonic irradiation twice, the impact strength of the blend rises sharply at 50–100 W ultrasonic intensity, and amounts to more than 900 J/m, 1.5 times as high as that of blend without ultrasonic irradiation. Scanning electron microscopy observation shows that with ultrasonic irradiation, morphology of uniform dispersed EPDM phase and good adhesion between EPDM and PP matrix was formed in PP/EPDM blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3519–3525, 2003     

Recycling of EPDM waste. II. Replacement of virgin rubber by ground EPDM vulcanizate in EPDM/PP thermoplastic elastomeric composition

Virgin ethylene propylene diene monomer (EPDM) rubber in a thermoplastic elastomeric blend of polypropylene (PP) and EPDM rubber was substituted by ground EPDM vulcanizate of known composition, after which the mechanical properties of the raw EPDM/waste EPDM/PP blends were determined. The ratio of the rubber content in the waste EPDM (r‐W‐EPDM) to the raw EPDM (R‐EPDM) in the blends was varied from 0 : 100 to 45 : 55. Attempts to replace higher amounts (>45%) of R‐EPDM by W‐EPDM failed because of processing difficulty. Although a drop in mechanical properties of the blends was observed at lower loadings of W‐EPDM, the properties showed improvement at intermediate W‐EPDM loadings. The R‐EPDM/W–EPDM/PP blends were found to be reprocessable. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3304–3312, 2001     

废胶粉填充改性PP复合材料

采用熔融挤出共混的方法,选用三种废胶粉填充聚丙烯(PP),制备了PP/废胶粉复合材料,研究了废胶粉质量分数对复合材料力学性能的影响.结果表明:废旧三元乙丙橡胶粉可明显提高复合材料冲击强度和拉伸断裂应变,当其质量分数为60%时,简支梁缺口冲击强度可提高33%,拉伸断裂应变增大了26%,有显著的增韧效果:废旧杂胶粉的加入使...     

Morphology and properties of PP/EPDM binary blends and PP/EPDM/nano‐CaCO3 ternary blends

In this article, the morphology, crystallization, and rheological behaviors of polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) binary blend and PP/EPDM/calcium carbonate nanoparticles (nano‐CaCO₃) ternary blend were investigated. Two processing methods, i.e., direct extrusion and two‐step extrusion, were employed to prepare the PP/EPDM/CaCO₃ blend. The influence of EPDM and nano‐CaCO₃ respectively on phase morphology and properties of PP/EPDM blend and PP/EPDM/CaCO₃ blend were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic rheometer. The crystallinity and crystallization temperature of PP/EPDM blend were improved in comparison to pure PP due to addition of EPDM, but kept invariable with the increased EPDM loading. As the EPDM content was increased, the mobility of PP molecular chains was weakened. Compared with direct extruded blend, less and finer nano‐CaCO₃ was dispersed in matrix of two‐step extruded blend. Accordingly, the increased nano‐CaCO₃ in matrix gave rise to a weaker increment in crystallinity and crystallization temperature of two‐step extruded blend, and a later platform of tanδ curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Dynamic rheology–morphology relationship of PP/EPDM blends prepared by melt mixing under Sc-CO2

It was demonstrated that the high mixing efficiency of twin screw extruder (TSE) helped to disperse the ethylene–propylene–diene terpolymer (EPDM) domains in polypropylene (PP) matrix, but could not lead to the uniform distribution of EPDM phase with small sizes because of the thermodynamical immiscibility between PP and EPDM. So supercritical carbon dioxide (Sc-CO₂) was environmentally and economically introduced to the twin screw extrusion to assist the melt mixing of PP and EPDM. The scanning electron microscopy photographs showed that co-continuous phase morphology was formed to some extent for the PP/EPDM 60/40 blend prepared with Sc-CO₂, especially with 2.5 wt% Sc-CO₂. This was the one important reason for that the complex viscosity and storage modulus of PP/EPDM 60/40 blend increased with the increase of Sc-CO₂ concentration.     

Miscibility of blends of ethylene‐propylene‐diene terpolymer and polypropylene

The miscibility of polymers is not only an important basis for selecting a proper blending method, but it is also one of the key factors in determining the morphology and properties of the blends. The miscibility between ethylene‐propylene‐diene terpolymer (EPDM) and polypropylene (PP) was explored by means of dynamic mechanical thermal analysis, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The results showed that a decrease in the PP content and an increase of the crosslinking density of EPDM in the EPDM/PP blends caused the glass‐transition temperature peaks of EPDM to shift from a lower temperature to higher one, yet there was almost no variance in the glass‐transition temperature peaks of PP and the degree of crystallinity of PP decreased. It was observed that the blends prepared with different mixing equipment, such as a single‐screw extruder and an open mill, had different mechanical properties and blends prepared with the former had better mechanical properties than those prepared with the latter. The TEM micrographs revealed that the blends were composed of two phases: a bright, light PP phase and a dark EPDM phase. As the crosslinking degree of EPDM increased, the interface between the phases of EPDM and PP was less defined and the EPDM gradually dispersed in the PP phase became a continuous phase. The results indicated that EPDM and PP were both partially miscible. The mechanical properties of the blends had a lot to do with the blend morphology and the miscibility between the blend components. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 315–322, 2002     

EPDM/聚烯烃共混型热塑性弹性体的研究

制备ＥＰＤＭ／聚烯烃简单共混型热塑性弹性体。研究了聚合物种类、橡塑比、二元和三元共混对共混物力学性能的影响。结果表明，部分结晶性ＥＰＤＭ共混物的力学性能比无定形ＥＰＤＭ共混物好，部分结晶性ＥＰＤＭ与ＬＤＰＥ（低密度聚乙烯）共混物的拉伸强度大于两者的加和值，而其它二元共混物的拉伸强度均低于两共混单元的加和值；用ＬＤＰＥ部分替代ＰＰ，或用氯磺化聚乙烯（ＣＳＭ）部分替代结晶性ＥＰＤＭ进行三元共混，能改善部分结晶性ＥＰＤＭ／ＰＰ共混物的某些性能。     

高模量弹性体对PP结晶行为及力学性能的影响

应用DSC和力学性能测试研究了PP/OTE、PP/EPDM共混物的结晶行为和它们的增韧作用。结果表明 ,烯烃类热塑性弹性体 (以下简称OTE)对PP的结晶性能无明显影响 ,EPDM对PP成核速率有促进作用。PP/OTE在赋予PP较好低温韧性的同时 ,使共混物的刚性得以适度兼顾 ,且易于加工。PP/OTE共混体系的综合性能优于PP/EPDM共混物     

Mechanical properties and morphological structures relationship of blends based on sulfated EPDM ionomer and polypropylene

The mechanical properties and morphological structures of blends based on Zn²⁺ neutralized low degree sulfated ethylene propylene diene monomer rubber (Zn–SEPDM) ionomer and polypropylene (PP) were studied. It was found that Zn²⁺ neutralized low degree sulfated EPDM ionomer and PP blends, which are new thermoplastic elastomeric materials, have better mechanical properties than those of PP/EPDM blend. Theoretical analysis of tensile data suggests that there is an increase of the extent of interaction between PP and EPDM in the presence of a low degree of Zn²⁺, which is also an indicator of better interfacial adhesion between PP and Zn–SEPDM than that between PP and EPDM. SEM results proved that the finer dispersed phase sizes and the shorter interparticle distances are the main reasons for the improved mechanical properties of the PP/EPDM blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1504–1510, 2004     

Recycling of commingled plastics waste containing polypropylene,polyethylene, and paper

Polymer waste recycling is a major technical problem, because large amounts of synthetic polymers are produced every day and polymeric wastes are gathered from municipal solid wastes. There are a few polyolefins, such as polyethylene (PE) and polypropylene (PP) with huge amounts of paper in the waste materials. In order to recycle the commingled plastics waste that contains paper, hydrolytic treatment is needed prior to conventional processing. In this project, the optimum conditions of hydrolytic treatment of paper and the mechanical properties and morphological state of different compositions of PP high‐density PE (HDPE) blends with paper were studied. Ethylene‐propylene‐diene copolymer (EPDM) was added to improve the mechanical properties of blends. The results show that the hydrolytic treatment of paper improves the mechanical properties, such as the tensile strength and modulus of the PP/HDPE/paper composites relative to the untreated samples, and up to 30% paper can be added to commingled PP and HDPE blends. The EPDM was used as an impact modifier. The plastics waste containing paper can be used in applications such as artificial wood. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2573–2577, 2001     

Mechanical Properties and Morphology of Ternary PP/EPDM/PE Blends

The ternary blends of high‐density polyethylene (PE), EPDM terpolymer and polypropylene (PP) have been used as a model low interfacial tension system to study encapsulation dynamics in ternary blends and their relation to the blends' mechanical properties. It was found that the modulus, tensile strength and impact resistance can be improved by PE addition if the PE is localized within the EPDM phase. A range of blend morphology was found depending on the PE viscosity and polymer incorporation sequence in the twin‐screw extruder. In the most favorable sequence, PE and EPDM were mixed together prior to their dispersion in the PP matrix. This practice resulted in a 50% increase in impact resistance when compared to mixing the three components in a single‐step.     

Modification of Ethylene Propylene Diene Terpolymer Rubber by Some Thermoplastic Polymers

Abstract

Blends of ethylene propylene diene terpolymer (EPDM) rubber with thermoplastic polyolefins such as low‐density polyethylene (LDPE), high‐density polyethylene (HDPE), high molecular weight polypropylene (PP), and polypropylene random copolymer grade (PP‐R) were prepared by melt mixing. The physico‐mechanical properties, equilibrium swelling in benzene, and aging properties of the binary blends were investigated, analyzing the effect of the rubber/thermoplastics ratio and the type of the thermoplastic material on these properties. The data obtained indicate that EPDM/PP‐R blend in 20/80 w/w% shows the highest physico‐mechanical properties with improved retained tensile strength at 90°C for 7 days. This blend ratio also gives excellent retained equilibrium swelling in benzene at room temperature for 7 days, although EPDM/LDPE blend in 80/20 w/w% imparts the highest retained elongation at break at 90°C for 7 days.     

In situ compatibilization of PP/EPDM blends during ultrasound aided extrusion

Blends of isotactic polypropylene (iPP) and uncured ethylene-propylene diene rubber (EPDM) of various concentrations were treated by high power ultrasonic waves during extrusion. Die pressure and power consumption were measured. The effects of different gap sizes, blend ratios and number of ultrasonic horns were investigated. The rheological properties, morphology and mechanical properties of the blends with and without ultrasonic treatment were studied. In situ compatibilization of the blends was observed as evident by their more stable morphology after annealing, improved mechanical properties and IR spectra. The obtained results indicated that ultrasonic treatment induced the thermo-mechanical degradations and led to the possibility of enhanced molecular transport and chemical reactions at the interfaces. Processing conditions were established for enhanced in situ compatibilization of the PP/EPDM blends.     

Electrical and flammability properties of alumina trihydrate filled polypropylene/ethylene propylene diene monomer composites as insulators in cable applications

Polymeric insulators role in power systems and insulation is one of the most important subjects in high voltage applications. This study investigates the effect of alumina trihydrate (ATH) loading on electrical and flammability properties of polypropylene (PP)/ethylene propylene diene monomer (EPDM) blend. ATH fillers were incorporated into the matrix to improve the tracking and flammability resistance of the composites. PP/EPDM (60:40) was used as matrix and compounding of ATH filled PP/EPDM composites was done using a twin‐screw extruder. Electrical and flammability tests of composites were performed. The results show that flammability decreased with increasing ATH loading in PP/EPDM composites. The effects of electrical stresses are investigated by measuring the carbon tracking (CT) and leakage current (LC) on the surface of composites. The CT and LC of PP/EPDM/ATH composites were found to decrease with increasing ATH content; however calculating the normalized degradation index (NDI) illustrated that all the sample were in accepted range. Field emission scanning electron microscope was used to relate the electrical properties with the morphological analysis, which showed that addition of ATH prevents the degradation of the matrix. POLYM. ENG. SCI., 54:493–498, 2014. © 2013 Society of Plastics Engineers     

低硬度EPDM/PP热塑性动态硫化胶Ⅱ.制备工艺条件对微观相态结构的影响

通过正交试验设计,研究了低硬度EPDM/PP共混型热塑性动态硫化胶的反应挤出动态硫化制备工艺,初步探讨了机筒温度、喂料螺杆驱动电压及主机螺杆转速等主要工艺因素对挤出物徽观相态结构的影响。     

Interfacial adhesion through maleic anhydride grafting of EPDM in PP/EPDM blend

This paper presents a study of interface modification effect through the use of maleic anhydride (MAH) grafting on one of the component polymers of the binary blend. The system used is binary blend of polypropylene (PP) and the elastomer EPDM (copolymer of ethylene–propylene–diene monomer). Two sets of the blend (i) PP/EPDM binary blend and (ii) PP/EPDM‐g‐MAH binary blend at constant degree of grafting (i.e., EPDM : MAH ratio) and at varying blending ratios were studied and compared for the properties and structure development. Results are discussed to illustrate the effect of interfacial modification due to presence of MAH by comparing the data of mechanical properties and crystallization behavior for the two sets of the binary blend at identical blending ratios, as well as to study the trends of variation of properties with blending ratio for each individual set of the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5528–5532, 2006     

三元乙丙橡胶/聚丙烯动态硫化热塑性弹性体的相态结构

用扫描电镜研究了三元乙丙橡胶(EPDM)聚/丙烯(PP)动态硫化热塑性弹性体(TPV)相态结构的形成过程,探讨了交联密度、制备工艺、螺杆转速对EPDM/PP TPV相态结构的影响。结果表明,采用以酚醛树脂为硫化剂的动态硫化工艺制备的EPDM/PP TPV,其相态结构实现了由EPDM和PP组成的双连续相到以EPDM为分散相、PP为连续相的转变;当硫化剂用量为7份时,橡胶相硫化速率和交联密度最大;当螺杆转速为180 r/m in时,反应性挤出工艺较之密炼机工艺制备的EPDM/PP TPV的橡胶粒子更细小、分散更均匀。     

Comprehensively improved mechanical properties of silane crosslinked polypropylene/ethylene propylene diene monomer elastomer blends

The properties and structure of silane crosslinked polypropylene (PP)/ethylene propylene diene monomer (EPDM) elastomer blends had been carried out. Fourier transform infrared spectroscopy and gel content tests were employed to evaluate the crosslinking reaction of PP/EPDM blends. Crosslinking efficiency of PP/EPDM blends was investigated using thermogravimetric analysis, differential scanning calorimeter, dynamic mechanical analysis, dynamic rheology, and tensile testing. Tanδ curves of silane crosslinked PP/EPDM blends exhibited an obvious “gel point” originated from the formation of dynamic crosslinking network. The blend corresponding to the “gel point” presented comprehensively improved mechanical properties. These results demonstrated that characteristic rheological parameters showed close correlations with key mechanical properties of silane crosslinked PP/EPDM blends. Scanning electron microscopy images illustrated that crosslinking had remarkably changed the morphologies of PP/EPDM blends. The large deformation mechanism of these blends had been suggested.     

PET/PC blends: Effect of chain extender and impact strength modifier on their structure and properties

Methylene diphenyl diisocyanate (MDI) affects the morphology, rheological, mechanical, and relaxation properties, as well as tendency to crystallize of PET in PET/PC/(PP/EPDM) ternary blends produced by the reactive extrusion. Irrespective of the blend phase structure, the introduction of MDI increases the melt viscosity (MFI dropped), resulting from an increase in the molecular weight of the polymer chains; the PET crystallinity was also reduced. MDI favors compatibility of PET with PC in PET/PC/(PP/EPDM) blends. This is explained by intensified interphase interactions on the level of segments of macromolecules as well as monomer units. The presence of MDI causes a substantial rise in the dynamic shear modulus within the high‐elastic region of PET (for temperature range between T_g,PET and that of PET cold crystallization); the processes of PET cold crystallization and melt crystallization become retarded; the glass‐transition temperatures for PET and PC become closer to each other. MDI affects insignificantly the blend morphology or the character of interactions between the disperse PP/EPDM blend and PET/PC as a matrix. PP/EPDM reduces the intensity of interphase interactions in a PET/PC/(PP/EPDM), but a rise in the degree of material heterogeneity. MDI does not change the mechanism of impact break‐down in the ternary blends mentioned above. Increased impact strength of MDI‐modified materials can be explained by higher cohesive strength and resistance to shear flow at impact loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011