Waste and Virgin LDPE/PET Blends Compatibilized with an Ethylene‐Butyl Acrylate‐Glycidyl Methacrylate (EBAGMA) Terpolymer, 1

Summary: This work is aimed at studying the morphology and the mechanical properties of blends of low density polyethylene (LDPE) and poly(ethylene terephthalate) (PET) (10, 20, and 30 wt.‐% of PET), obtained as both virgin polymers and urban plastic waste, and the effect of a terpolymer of ethylene‐butyl acrylate‐glycidyl methacrylate (EBAGMA) as a compatibilizer. LDPE and PET are blended in a single screw extruder twice; the first extrusion to homogenize the two components, and the second to improve the compatibilization degree when the EBAGMA terpolymer is applied. Scanning electron microscopy (SEM) analysis shows that the fractured surface of both the virgin polymer and the waste binary blends is characterized by a gross phase segregation morphology that leads to the formation of large PET aggregates (10–50 µm). Furthermore, a sharp decrease in the elongation at break and impact strength is observed, which denotes the brittleness of the binary blends. The addition of the EBAGMA terpolymer to the binary LDPE/PET blends reduces the size of the PET inclusions to 1–5 µm with a finer dispersion, as a result of an improvement of the interfacial adhesion strength between LDPE and PET. Consequently, increases of the tensile properties and impact strength are observed.

SEM micrographs of the fracture surface of a waste 70/30 LDPE/PET blend (R30) and of its blend with 15 pph of EBAGMA (R30C). Magnification × 1 000.     

Evaluation of the Effectiveness of New Compatibilizers Based on EBAGMA‐LDPE and EBAGMA‐PET Masterbatches for LDPE/PET Blends

The present paper is aimed to evaluate the efficiency of two masterbatches, i.e., EBAGMA/LDPE (MB1) and EBAGMA/PET (MB2) with 50/50 w/w composition, prepared by melt mixing and used as new compatibilizers for blends of LDPE/PET. The morphology, the mechanical and the thermal properties of LDPE/PET/MB1 and LDPE/PET/MB2 ternary blends have been investigated. Morphological investigation by SEM of LDPE/PET/MB1 ternary blends showed a finer dispersion of PET in LDPE matrix with a better interfacial adhesion compared to those of both LDPE/PET/MB2 and binary LDPE/PET blends. The results also indicated a substantial improvement in both elongation at break and impact strength, while the Young's modulus decreased. Moreover, the thermal properties showed a decrease of the crystallization phenomena of PET in LDPE/PET/MB1 blend, thus confirming the good dispersion of PET particles into the continuous phase of LDPE matrix, leading to the conclusion that MB1 could be an efficient compatibilizer for LDPE/PET system.

     

Ethylene Butyl Acrylate Glycidyl Methacrylate Terpolymer as an Interfacial Agent for Isotactic Poly(propylene)/Wood Flour Composites

Summary: This paper presents the results of an experimental investigation concerning the use of an ethylene butyl acrylate and glycidyl methacrylate (EBAGMA) terpolymer as an interfacial agent for isotactic poly(propylene)/wood flour (iPP/WF) composites at various filler ratios (10, 20 and 30 wt.‐%). The effects of the EBAGMA terpolymer on the morphology, tensile properties, impact strength and water uptake of the iPP/WF composites were studied and the results were compared with those obtained with maleated poly(propylene) (MAPP) used as a compatibilizer. Initially, the mixing process was performed in a calendaring unit at 170 °C for pre‐homogenization of the filler in the matrix. Composites made out of these combinations were then ground and injected into a standard mold at 180 °C in the absence and the presence of compatibilizer. The results indicated that both EBAGMA terpolymer and MAPP improved the interactions between iPP and WF, and induced a better dispersion of wood particles in the polymer matrix, as revealed by scanning electron microscopy (SEM). Furthermore, tensile properties and impact strength were also increased. Another important effect was on the water absorption property, which was significantly lower for the samples with EBAGMA and MAPP. However, EBAGMA terpolymer produced better enhancement of the properties of the iPP/WF composites compared to the compatibilized samples with MAPP.

SEM micrographs of the fracture surface of iPP/WF composites (70/30 wt.‐%): (a) without compatibilizer; (b) with 10 pph EBAGMA; (c) with 10 pph MAPP. Magnification was ×500.     

MAH接枝LDPE对PET/LDPE共混物增容作用的研究

本文研究了马来酸酐(MAH)在引发剂过氧化二异丙苯(DCP)存在下,与LDPE在挤出机中进行熔融接枝反应,所得接枝物GPE对PET/LDPE共混体系的增容作用.共混物的冲击强度及应力应变曲线结果表明.GPE能明显改善共混体系的相容性,提高共混体系的冲击强度,仅用20%的GPE就能使共混物由脆性断裂变为韧性断裂.利用SEM观察共混物的冲击断面形貌,结果表明,PET与LDPE完全不相容,GPE能明显改善PET与LDPE共混物的相容性,使分散相颗粒细化.而DSC结果表明:PET/LDPE/GPE与PET/LDPE一样都是热力学不相容体系,共混物存在两相结构,PET与LDPE不形成共晶.GPE在共混物中仅起相间界面相容剂的作用.     

Structure and Morphology Development in Films of mLLDPE/LDPE Blends During Blowing

Summary: In this work the analysis of the structure orientation, morphology, relaxation time and optical properties of blown films of mLLDPE, LDPE and their blends were performed by using WAXD, SALS, AFM, DSC and rheological and haze tests. For mLLDPE film, the crystals do not present “a”‐axis orientation along the machine direction; a distinct spherulite like superstructure is seen. The film surface is very rough. The values of bulk and surface haze are higher than LDPE and blends, whereas the relaxation time is lower. For LDPE film the (110) planes are parallel and at same time twisted with respect to the layer of the film with the “a”‐axis well oriented along the machine direction. No spherulite superstructure is observed and the surface of the film is more regular. High values of relaxation time are observed. The surface haze is the predominant contribution to the total haze. For the blend films no clear and distinct spherulite structures are observed. The orientation degree increases with composition never approaching that of LDPE. The surface is very more regular and smooth than that of the pure polymers. The haze values are below the values of pure materials. It was underlined that bulk and surface morphology and orientation degree of the crystalline planes along the machine direction dictate the optical properties of the films. Moreover both orientation and morphology are defined by the PE molecular and melt rheology characteristics, processing conditions and blend composition.

Total, bulk and surface haze of mLLDPE/LDPE blend films as a function of composition.     

PET/TPEE共混物的结构与性能

通过熔融共混的方法制备不同组成的PET/TPEE共混物,并采用DSC、仪器化冲击仪和SEM等测试手段,对PET/TPEE共混体系的结构和冲击性能进行研究.DSC测试表明:PET/TPEE共混物中两组份仍保持着各自分子链的规整性,进一步加热两组分仍可以分别结晶.力学性能结果显示:在15%TPEE添加量条件下,TPEE可以有效地改善PET的冲击性能.同时SEM照片显示:冲击断面生成许多新层面,有助于冲击性能的改善.     

贮存稳定的LDPE/SBS共混物改性沥青的动态力学性能

利用应变控制流变仪对LDPE／SBS共混物改性沥青的动态力学性能进行了研究，考察了反应剂及其用量，LDPE／SBS共混物用量等对改性沥青高温性能的影响。结果表明，LDPE／SBS共混物的加入提高了原始沥青的高温模量，同时降低了其损耗角正切值，并且随着共混物用量的增加。沥青的高温性能也随之提高，温度敏感性也显著减弱。反应剂的加入使得沥青高温性能得到了更进一步的改善。改善程度随反应剂用量的增加而更加明显。     

核壳结构聚(丙烯酸丁酯/甲基丙烯酸十二酯)的制备

以丙烯酸丁酯(BA)为核单体,甲基丙烯酸十二酯(LMA)为壳单体,二甲基丙烯酸乙二醇酯(EGDMA)为交联剂,采用分阶段饥饿态加料方式和半连续乳液聚合方法合成了具有核壳结构的聚(丙烯酸丁酯/甲基丙烯酸十二酯)即P(BA/LMA)乳液。考察了乳化剂十二烷基硫酸钠(SDS)、引发剂过硫酸钾(KPS)和核壳单体配比对乳液性能的影响,结果表明,当复合乳化剂m(OP-10):m(SDS)为2:1且质量分数为4%左右,引发剂KPS质量分数为0.1%,单体m(LMA):m(BA)为55:45时,体系稳定,转化率高,成膜温度最低;研究了交联剂交联场所对聚合物结构的影响,结果表明核交联后形成了核壳结构。     

Morphology and mechanical properties of polyamide 12 blends with styrene/ethylene–butylene/styrene rubbers with and without maleation

Blends of polyamide 12 (PA12) with styrene/ethylene–butylene/styrene (SEBS) and maleic anhydride grafted SEBS (SEBS‐g‐MA) were prepared by twin‐screw extrusion and injection molding. The morphology, mechanical properties, and dynamic mechanical properties of the blends were studied. The morphology of the blends was evaluated from the etched surfaces of cryogenically fractured specimens with scanning electron microscopy. The morphological parameters showed that the PA12/SEBS‐g‐MA blends (PM series) exhibited a finer and more uniform rubber dispersion than the PA12/SEBS blends (PS series) because of the interfacial chemical reactions. SEBS functionalization via maleic anhydride grafting strongly affected the morphological parameters, such as the domain size, interfacial area per unit of volume, and critical interparticle distance, but the distribution of the rubber domains in the blends was less affected. Tensile and impact studies showed that the PS blends had worse mechanical properties than the PM blends. The tensile strength and elongation at break of the PM blends were considerably greater than those of the PS blends. The fracture toughness and energy values determined for notched Charpy specimens in high‐speed impact tests were markedly higher for the PM blends than for the PS blends. A similar observation was obtained from instrumented falling weight impact studies. Dynamic mechanical analysis confirmed the incompatibility of the blend components because the glass‐transition temperatures of PA12 and the rubber phase (SEBS and SEBS‐g‐MA) were not affected. © 2005 Wiley Periodicals, Inc. J Appl polym Sci 95: 1376–1387, 2005     

Impact Modification of Polylactide with a Biodegradable Ethylene/Acrylate Copolymer

The effectiveness and efficiency of an ethylene/acrylate copolymer in toughening semicrystalline and amorphous PLA through melt blending is studied. The mechanical properties, phase morphologies, miscibilities, and toughening mechanisms of the blends are assessed. The ethylene/acrylate impact modifier effectively improved the impact strength of the blends, regardless of the PLA type. The semicrystalline blends showed decreased tensile strength and modulus with increased impact modifier content. In contrast, the ductility, elongation at break, and energy to break increased significantly. The relatively low BDT temperature obtained for the PLA blends renders the ethylene/acrylate copolymer impact modifier a desirable additive to toughen PLA for use in cold temperatures.

     

Miscibility and fracture toughness of thermoplastic polyurethane/poly(vinyl chloride)/nitrile rubber ternary blends with special reference to the blend composition

Ternary blends of thermoplastic polyurethane and a poly(vinyl chloride)/nitrile rubber blend were investigated in this work. The blends, with weight ratios of 100/0, 80/20, 40/60, 60/40, 80/20, and 0/100, were prepared via melt blending. Dynamic mechanical analysis showed that the blends with ratios of 20/80 and 80/20 were miscible, whereas the 40/60 and 60/40 blends were partially miscible. IR spectroscopy studies showed shifts in the peaks due to specific interactions in the blends. The blends showed degradation behavior between the blend components. The fracture toughness was investigated with the J‐integral by the locus method; the components and the miscible blends had good fracture toughness, whereas the other blends had lower toughness. Similar behavior was observed for the tensile properties. Scanning electron microscopy studies showed the morphological variations in the blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1763–1770, 2005     

Correlations between composition and crystallinity of LDPE/HDPE blends

DMTA, DSC, WAXS and density were used to quantify the crystallinity and crystallite dimensions of specific grades of LDPE/HDPE blends. In virtue of the close agreement of the results obtained with the three techniques, an average degree of crystallinity was calculated, allowing the establishment of quantitative relationships between composition and crystallinity, and shifting of the α-relaxation. Dimensions along the 110 and 200 planes were also correlated with shifting of the α-transition.     

开口爽滑剂在低密度聚乙烯薄膜中的应用

介绍了目前我国低密度聚乙烯薄膜发展现状,开口剂和爽滑剂在低密度聚乙烯薄膜开口爽滑性方面的作用,分析了薄膜提高开口爽滑性的同时,如何兼顾较好光学性能,对国内低密度聚乙烯生产企业今后牌号升级及细化提出了建议。     

Properties of fatty-acid esters of starch and their blends with LDPE

In the present study, starch octanoates OCST1.8 and OCST2.7 with degrees of substitution (d.s.) of 1.8 and 2.7, respectively, and dodecanoate DODST2.7 (d.s. = 2.7), were prepared by esterification of native starch with fatty acid chlorides. Our analyses, including elemental analysis, FTIR, contact angle, DSC, and TGA measurements confirmed the esterification reaction of starch and the degree of substitution. The ester group was found to act like an internal plasticizer, with an increase in the number and the size of fatty acyl chains grafted onto starch. These starch esters were mixed with low density polyethylene (LDPE) at various proportions in a Haake Rheomixer. Water and moisture absorption, thermal and mechanical properties, and biodegradation were investigated as a function of blend composition. The DODST2.7/LDPE blends showed, in general, better thermal stability and higher elongation, but lower tensile strength and water absorption, than did corresponding OCST/LDPE blends. The addition of starch esters to LDPE led to a very slow rate of biodegradation of these blends. © 1997 John Wiley & Sons, Inc. J Appl Polym 65: 705–721, 1997     

Highly filled blends of a vinylic copolymer with plasticized lignin: Thermal and mechanical properties

The objective of this study was the development of new vinyl flooring formulations with increased resistance to attack by fungi and microorganisms, formulated with plasticizers having chemical compositions different from that of common dioctyl phthalate (DOP). Alkyl phthalate plasticizers are considered to be toxicological and ecotoxicological hazards, although this is still under debate. It is suspected that during the service life of poly(vinyl chloride) (PVC) flooring, the attack of fungi and microorganisms leads to the degradation of DOP and the release of some volatile organic compounds. For this reason, in the new flooring formulations, the vinyl chloride/vinyl acetate copolymer (VC–VAc) was partially replaced with lignin, a natural polymer and a major component of wood and vascular plants. Besides its other functions in wood, lignin imparts resistance to microorganisms. An organosolv lignin from Alcell Technologies, Inc. (AL), was used as a partial replacement of PVC. The influence of the new plasticizers, as well as the influence of the partial replacement of VC–VAc with lignin, on the morphology and thermal and mechanical properties of the composites was investigated with scanning electron microscopy, differential scanning calorimetry, and tensile testing. Butyl benzyl phthalate and diethylene glycol dibenzoate were used as plasticizers; both were compatible with PVC and AL. The results indicated that diethylene glycol dibenzoate was the best plasticizer for these blend composites. In these formulations, AL could replace up to 20 parts of the copolymer. At this level of replacement, the key mechanical properties of the new composites compared very favorably with those of the DOP control formulations. The obtained formulation will be tested further for resistance to fungi and microorganisms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2000–2010, 2003     

Impact Fracture and Failure Behavior of in‐situ Polymerized,Ethylene/Butyl Acrylate Rubber Toughened Polyamide‐12

The fracture and failure behavior of in‐situ polymerized polyamide‐12 (PA‐12) blends prepared by reactive extrusion were studied in instrumented high‐speed (v = 1.2 m/s) impact bending tests using the linear elastic fracture mechanics approach. PA‐12 was polymerized in presence (up to 9 wt.‐%) of ethylene/butyl acrylate copolymers (E/BA) of varying BA content and melt viscosity. From the tests performed on injection molded specimens at ambient temperature and –40°C, respectively, the fracture toughness (K_d) and initiation fracture energy (G_d,i) were derived. K_d was less sensitive to either testing temperature or E/BA type and content. G_d,i, on the other hand, went through a maximum at room temperature and monotonously increased at T = –40°C as a function of modifier content. E/BA with higher melt viscosity and lower polarity (lower BA content) performed better than the lower melt viscosity, higher polarity E/BA counterpart. The dominant failure modes and their change both with temperature and modifier content were studied by fractography and discussed.     

Improving transparency of stretched PET/MXD6 blends by modifying PET with isophthalate

Compatibilized blends of PET and MXD6 have good transparency because their refractive indices match closely. However, haziness is observed when the blends are stretched because stretching imparts greater refractive index anisotropy to PET than to MXD6. Analysis of the strain-dependent birefringence reveals that different molecular deformation models describe the intrinsic birefringence of PET and MXD6. This study focuses on reducing the intrinsic birefringence of PET by partially replacing terephthalate with isophthalate. Statistical copolymers are prepared by conventional copolymerization of the monomers. Alternatively, blocky copolymers are obtained by melt blending PET with poly(ethylene isophthalate) (PEI). A close refractive index match with stretched MXD6 is achieved with copolymers containing 15-20% isophthalate. Statistical copolymers in this composition range are not satisfactory for blending because they have low molecular weight and are difficult to stretch. However, blocky copolymers containing 15-20% isophthalate form blends that stretch readily. After biaxial stretching, transparency of blends with 10 wt% MXD6 approaches that of PET. Good transparency of the blends is validated with stretch-blown bottle walls. Oxygen transport measurements confirm that partial replacement of terephthalate with isophthalate does not affect the good gas barrier properties of biaxially stretched PET blends.     

光固化聚氨酯甲基丙烯酸酯胶/环氧丙烯酸酯胶共混体系的结构与性能

在本文中,将自己合成的聚氨酯甲基丙烯酸酯胶与环氧丙烯酸酯胶共混,用扫描电镜,扭辫仪,力学性能测定仪等对该共混体系的相结构,玻璃化转变温度,相容性及力学性能等进行了研究,结果表明,这两种胶分子间作用力较强,它们的相容性很好,聚氨酯甲基丙烯酸酯胶具有较好的低温韧性,而环氧丙烯酸酯胶在26度下的拉伸性能较好,故可通过加入少量聚氨酯甲基丙烯酸酯胶改善环氧丙酸酯胶的低温脆性,加入少量环氧丙烯酸酯胶改善聚氨酯甲基丙烯酸酯胶在26度下的拉伸性能。     

Reactive compatibilization of PA6/LDPE blends with an ethylene-acrylic acid copolymer and a low molar mass bis-oxazoline

A sample of polyamide-6 (PA) was blended with low density polyethylene (LDPE) in the 80/20 wt/wt ratio, either without and with 2 phr of an ethylene-acrylic acid copolymer (EAA), Which was known to behave as a compatibilizer precursor, and the effect of the addition of small amounts (0.2 or 0.35 phr) of a fourth component, 2,2′-(1,3-phenylene)-bis(2-oxazoline) (PBO), was investigated. The reactions of PBO with EAA, PA and their blends were studied by recording as a function of time the torque applied to the blending apparatuses and by studying the solubility behavior of the products in formic acid. The PALDPE blends were prepared in a co-rotating twin screw extruder and were characterized by Molau tests, differential scanning calorimetry, scanning electron microscopy, rheology, and determination of the ultimate mechanical properties, including impact tests. The results indicate that the effectiveness of EAA as a compatibilizer precursor is considerably enhanced when PBO is added into the blends. It is thought that the reactions of PBO with the free carboxyl groups of EAA and with the amine or carboxyl end groups of PA run, at least in part, toward the formation of PA-g-EAA copolymers acting as the true compatibilizers for these blends.     

Fabrication of super‐ductile PP/LDPE blended parts with a chemical blowing agent

The mechanical blending of polypropylene (PP) and low density polyethylene (LDPE) is an economical and simple method for producing new polymeric materials for specific applications. However, the reduction in strain‐at‐break of the blend is one of its main shortcomings. In this study, PP/LDPE foamed parts were fabricated by conventional injection molding (CIM) with azodicarbonamide as a chemical blowing agent (CBA) and tested for tensile properties at two test speeds. Also, the fracture surfaces of the parts were investigated by scanning electron microscopy (SEM). In addition, to investigate the underlying mechanism of the super‐ductility, the tested samples were carefully analyzed and compared, and further characterized by differential scanning calorimetry and SEM. The results suggest that fabricating PP/LDPE super‐ductile parts using CIM with a CBA is feasible. The results also indicate that there is a close relationship between the mechanical properties and morphological structures, which are deeply influenced by the dosage of CBA, the PP/LDPE ratio, and the packing parameters. Furthermore, compared to conventional injection molded solid parts, the ductility of the foamed parts can be dramatically improved by the formation of microfibrils in the PP phase, which come into being under certain processing conditions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44101.