Influence of high density polyethylene‐g‐maleic anhydride on compatibility and properties of poly(butylene terephthalate)/high density polyethylene blends

Poly(butylene terephthalate)/high density polyethylene (PBT/HDPE) blends and PBT/HDPE‐grafted maleic anhydride (PBT/HDPE‐g‐MAH) blends were prepared by the reactive extrusion approach, and the effect of blend compositions on the morphologies and properties of PBT/HDPE blends and PBT/HDPE‐g‐MAH blends was studied in detail. The results showed that flexural strength, tensile strength, and notched impact strength of PBT/HDPE blends decreased with the addition of HDPE, and flexural strength and tensile strength of PBT/HDPE‐g‐MAH blends decreased, while the notched impact strength of PBT/HDPE‐g‐MAH increased with the addition of HDPE‐g‐MAH. Compared with PBT/HDPE blends, the dimension of the dispersed phase particles in PBT/HDPE‐g‐MAH blends was decreased and the interfacial adhesion was increased. On the other hand, the effects of HDPE and HDPE‐g‐MAH contents on the crystalline and the rheological properties of the blends were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6081–6087, 2006     

Structure and properties of ultraviolet‐irradiated high density polyethylene at different environmental temperatures

C? O, C?O, and C(?O)O oxygen‐containing groups were introduced onto the molecular chain of high‐density polyethylene (HDPE) through ultraviolet irradiation in air. The introduction rate of the oxygen‐containing groups onto HDPE increased with increasing environmental temperature. After ultraviolet irradiation, the molecular weight of HDPE decreased, and its distribution became wider; the melting temperature, contact angle with water, and impact strength decreased; the degree of crystallinity and yield strength increased; and their variation amplitude increased with environmental temperature. The environmental temperature had an effect on the gel content of irradiated HDPE. HDPE‐irradiated for 48 h at 35° and 50°C were not crosslinked. However, gelation took place in HDPE irradiated for 24 h at 70°C. HDPE irradiated at a high environmental temperature was more effective than that irradiated at a low environmental temperature in compatibilizing HDPE with PVA. Compared with the 83/17 HDPE/PVA blend, the yield and notched impact strength of the 73/17 HDPE/PVA blend compatibilized with 10% HDPE irradiated for 24 h at an environmental temperature of 70°C increased from 30.8 MPa and 110 J/m to 34.9 MPa and 142 J/m, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2966–2969, 2003     

Studies on Structure and Properties of HDPE Functionalized Through Ultraviolet Irradiation and Its Blends with CaCO3

Abstract

The structure and properties of high-density polyethylene (HDPE) functionalized through ultraviolet irradiation in air and its blends with CaCO₃ were studied by Fourier transfer infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), contact angle measurement, Molau test, and mechanical properties test. The experimental results reveals that oxygen-containing groups such as C = O and C - O were introduced onto the molecular chains of HDPE through ultraviolet irradiation in air, and the groups' concentration increases with irradiation time. After irradiation, the water contact angle of HDPE becomes smaller, showing that the hydrophilicity of irradiated HDPE increases. Compared with those of HDPE/CaCO₃ blend, the dispersion of CaCO₃ particles in irradiated HDPE/CaCO₃ blend, the interface interaction between CaCO₃ particles and irradiated HDPE matrix, and the mechanical properties of irradiated HDPE/CaCO₃ blend are improved due to the introduction of polar groups.     

增容剂对HDPE/PC共混体系性能的影响

系统研究了增容剂（LDPE-g-DABPA)对高密度聚乙烯（HDPE）／聚碳酸酯（PC）共混体系形态及拉伸性能、冲击性能、热性能、流动性能的影响，确定了增容剂的最佳用量。结果表明，在HDPE／PC／LDPE-g-DABPA为85／15／16时，体系拉伸强度没有变化，而冲击强度由未增容的13．86kJ/m增加到55．31kJ/m，提高了3倍，MFR由1．65g/10min增加到2．16g/10min，用裂纹扩展功（G1c)评价LDPE-g-DABPA的增容效果，结果表明，体系的G1c由增容前的0．0955J增加到0．2025J，说明LDPE-g-DABPA有良好的增容作用。     

Studies on Linear Low-Density Polyethylene Functionalized by Ultraviolet Irradiation and Its Compatibilization

Summary Some groups containing oxygen such as C-O, C-OH and C=O were introduced onto the molecular chains of linear low-density polyethylene (LLDPE) through ultraviolet irradiation in air. The concentration of these groups containing oxygen increased with increasing irradiation time. After irradiation, the molecular weight of the LLDPE decreased, and its distribution widened. It was found that the gelation occurred after the LLDPE was irradiated for 12 h, and the gel content increased with increasing irradiation time. The crystal shape and space of the crystalline plane for irradiated LLDPE remained. Compared with those of LLDPE, the melt flow index, tensile strength and elongation at break of the irradiated LLDPE decreased, but its hydrophilicity increased and its toughness retained good. The polyamide 66 (PA66)/LLDPE/irradiated LLDPE blends were prepared by blending a small percentage of irradiated LLDPE with PA66. The melting temperature and crystallinity of both the LLDPE and PA66 components in the blends decreased with increasing irradiation time. The compatibility, dispersion and interfacial interaction between PA66 and LLDPE were improved after blending. With the addition of 5% LLDPE irradiated for 36 h, the tensile strength, bending strength and notched impact strength of the blends was enhanced from 48.3 MPa, 64.8 MPa and 30.8 J/m to 57.4 MPa, 71.5 MPa and 101.2 J/m, respectively.     

HDPE/UHMWPE共混物的制备及其性能

采用不同螺纹块组合的双螺杆挤出机制备HDPE/UHMWPE共混物,研究UHMWPE用量、螺杆结构对共混物力学性能、流变行为及分散形态的影响.结果表明:随着UHMWPE用量的增加,共混物的拉伸和缺口冲击强度随之增加,特殊螺杆挤出机制备共混物的机械性能均比普通螺杆的提高.UHMWPE使共混物成型加工黏度增大,特殊螺杆能降低共混物成型加工黏度.偏光显微镜照片显示,特殊双螺杆挤出机使UHMWPE熔融程度和分散程度增大.     

紫外辐照官能化HDPE的研究

本文通过红引光谱,与水的接触角以及力学性能测试等研究了空气中紫外辐照ＨＤＰＥ官能化及其增容作用。表明,紫外辐照能有效地在ＨＤＰＥ分子链上引入Ｃ≡Ｏ基团,随辐照时间增加,ｕＨＤＰＥ的Ｃ≡Ｏ基团含量南昌市,与水的接触角一上降,在一定条件下制得的ｕＨＤＰＥ对ＨＤＰＥ／ＰＣ共混体系有增容作用,其共涨物的拉伸强度、断裂伸长率和缺口冲击强度比未增容的都有提高。     

Mechanical Properties and Crystal Structure of HDPE Induced by Small Amount of High-molecular-weight and Low-molecular-weight Polyethylene under Shear Stress Produced by Dynamic Packing Injection Molding

In order to better understand the effect of small amount of both high-molecular-weight polyethylene (HMWPE) and low-molecular-weight polyethylene (LMWPE) on the mechanical properties and crystal morphology under the shear stress field, the dynamic packing injection molding (DPIM) was used to prepare the oriented pure polyethylene samples and its blends ones with different contents of HMWPE and LMWPE. The experiment substantiated that the further improvement of tensile strength and impact stength along the flow direction (MD) of HDPE/HMWPE/LMWPE samples was achieved, while the tensile strength along the transverse direction (TD) still substantially exceeded that of conventional molding. When the contents of HMWPE and LMWPE were respectively 8% in blends, the tensile strength in both flow and transverse directions of the samples were highly enhanced, with improvements from 27.75 MPa to 115.43 MPa (about 316%), in MD and from 23MPa to 32.74 MPa (about 42.34%), in TD; besides the impact strength was improved from 21.55 KJ/m² to 72.6 KJ/m² (about 236.89%), in MD but decreased from 17 KJ/m² to 6.92 KJ/m² in TD. The obtained samples were characterized via DSC, WAXD and SEM. For HDPE/HMWPE/LMWPE, the shish-kebab structure which is composed of stretched chains (shish) and lamellae (kebab) was seen in the oriented region of DPIM samples and the spherulites existed in the oriented region of SPIM samples. Furthermore, the appropriate amount HMWPE and LMWPE (about 8%, respectively) blended into mixture can improve the thickness and the length of lamellae, and the degree of crystallinity in shear region by DPIM which were approved by DSC and SEM, at the same time, it can also enhance the intensity of orientation of lamellae in shear region confirmed by SEM and WAXD. The reason of improvement of mechanical properties is the existence of these thicker, longer and more orientated lamellae in shear region.     

HDPE及增韧HDPE的力学性能与测试条件的关系

于23℃时,研究了拉伸、弯曲速度及试样缺口剩余宽度对高密度聚乙烯(HDPE)、HDPE/弹性体、HDPE/E型增韧母料(E-TMB)的拉伸、弯曲及冲击强度等力学性能的影响。结果表明,所研究的测试条件对这三种材料力学性能影响的程度不同:对于这三种材料,均是拉伸速度对拉伸屈服应力、弹性模量影响的程度较小,对断裂伸长率影响的程度较大,弯曲速度对弯曲弹性模量、弯曲强度影响的程度较大;三种材料中,拉伸速度对断裂伸长率影响程度最大的是HDPE/弹性体,最小的是HDPE/E-TMB,弯曲速度对弯曲弹性模量、弯曲强度影响程度最大的是HDPE/E-TMB,最小的是HDPE/弹性体;随外力作用速度增大性能并非匀速变化,对不同的材料、不同的性能有相应的敏感区;试样缺口剩余宽度对HDPE/E-TMB的悬臂梁缺口冲击强度影响程度较大,而且缺口剩余宽度由7.8mm增加到8.0mm是影响的敏感区,对HDPE、HDPE/弹性体的影响的程度很小。     

Structure and properties of PP/POE/HDPE blends

This work was aimed to counteract the effect of ethylene‐α‐olefin copolymers (POE) by reinforcing the polypropylene (PP)/POE blends with high density polyethylene (HDPE) particles and, thus, achieved a balance between toughness and strength for the PP/POE/HDPE blends. The results showed that addition of HDPE resulted in an increasing wide stress plateau and more ductile fracture behavior. With the increase of HDPE content, the elongation at break of the blends increased rapidly without obvious decrease of yield strength and Young's modulus, and the notched izod impact strength of the blends can reach as high as 63 kJ/m² at 20 wt % HDPE loading. The storage modulus of PP blends increased and the glass transition temperature of each component of the blends shifted close to each other when HDPE was added. The crystallization of HDPE phase led to an increase of the total crystallinity of the blend. With increasing HDPE content, the dispersed POE particle size was obviously decreased, and the interparticle distance was effectively reduced and the blend rearranged into much more and obvious core‐shell structure. The fracture surface also changed from irregular striation to the regularly distant striations, displaying much obvious character of tough fracture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Remarkable effects of silicone rubber on flame retardant property and mechanical properties of crosslinked high-density polyethylene/bio-based magnesium phosphate flame retardant (MHPA) composite

In this paper, a new bio-based flame retardant MHPA was prepared by the reaction of magnesium hydroxide (MH) and phytic acid (PA). Then the crosslinked high-density polyethylene (HDPE) flame-retardant composite was prepared by adding it and silicone rubber (SR) into HDPE and using electron beam irradiation. The test results of limiting oxygen index (LOI) and cone calorimeter test (CCT) show that the combination of MHPA and SR can increase the flame retardancy and smoke suppression performance of HDPE. The LOI of HDPE composite with 10 parts of SR is 28.3%, and its pHRR, THR and TSP values are reduced to 454.1 kW/m², 99.7 MJ/m² and 8.3 m², respectively, which is because MHPA and SR jointly promote the formation of continuous and high-density carbon slag in the combustion process of HDPE and inhibit the penetration of flame. In addition, the HDPE composite with 10 parts of SR has significant tensile strength, elongation breaking strength and tear strength, because SR can produce continuous stable structure with HDPE after irradiation and crosslinking. Therefore, this study verified that MHPA and SR together can effectively improve the flame retardancy, smoke suppression and mechanical properties of HDPE composite.     

Extrusion of ultrahigh molecular weight polyethylene under ultrasonic vibration field

The effects of polypropylene (PP) and ultrasonic irradiation on the processing and mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE) are studied. The results show that PP can effectively improve the fluidity and mechanical properties of UHMWPE. The Izod notched impact strength increases from 92 kJ/m² for pure UHMWPE to 109.2 kJ/m² for the blend of UHMWPE with 10 wt % PP. The Young's modulus increases from 528 MPa for pure UHMWPE to 1128 MPa when 25 wt % PP is contained in the blend, and the yield strength also rises when PP is added. The application of ultrasonic vibrations during extrusion can prominently decrease the die pressure and apparent viscosity of the melt, thus increasing the output of extrudate. An appropriate ultrasonic intensity and irradiation time can further promote the mechanical properties, while an overdose of irradiation destroys them. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2628–2632, 2003     

Preparation of HDPE/SEBS‐g‐MAH and its effect on mechanical properties of HDPE/wood flour composites

In this article, high density polyethylene/styrene‐ethylene‐butylene‐styrene block copolymer blends (HDPE/SEBS) grafted by maleic anhydride (HDPE/SEBS‐g‐MAH), which is an effective compatibilizer for HDPE/wood flour composites was prepared by means of torque rheometer with different contents of maleic anhydride (MAH). The experimental results indicated that MAH indeed grafted on HDPE/SEBS by FTIR analysis and the torque increased with increasing the content of maleic anhydride and dicumyl peroxide (DCP). Styrene may increase the graft reaction rate of MAH and HDPE/SEBS. When HDPE/SEBS MAH was added to HDPE/wood flour composites, tensile strength and flexural strength of composites can reach 25.9 and 34.8 MPa in comparison of 16.5 and 23.8 MPa (without HDPE/SEBS‐g‐MAH), increasing by 157 and 146%, respectively. Due to incorporation of thermoplastic elastomer in HDPE/SEBS‐g‐MAH, the Notched Izod impact strength reached 5.08 kJ m^?2, increasing by 145% in comparison of system without compatibilizer. That HDPE/SEBS‐g‐MAH improved the compatibility was also conformed by dynamic mechanical measurement. Scanning electron micrographs provided evidence for strong adhesion between wood flour and HDPE matrix with addition of HDPE/SEBS‐g‐MAH. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of electron beam irradiation on mechanical properties of high density polyethylene and its blends with sericite‐tridymite‐cristobalite

Some oxygen containing groups (mainly the CO group) are formed on the molecular chain of high density polyethylene (HDPE) during electron beam irradiation in air. The affinity between HDPE and sericite‐tridymite‐cristobalite (STC), the dispersion of STC in the HDPE matrix, and the mechanical properties of the HDPE/STC blend are improved quite a lot by the introduction of polar groups. Compared with HDPE, the tensile and impact strength of electron beam irradiated HDPE (30 kGy)/STC (60/40) are increased to 29.0 MPa and 518 J/m, respectively, from 24.5 MPa and 215 J/m; the tensile and impact strength of irradiated HDPE (30 kGy)/STC (50/50) are 31.1 MPa and 424 J/m, respectively. The Ceast impact test showed that the increase of impact strength was mainly due to the strong interfacial adhesion between irradiated HDPE and STC, thus preventing the spreading of cracks over wide areas. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 243–249, 2000     

Mechanical properties and interfacial interaction of CaCO3 filled HDPE compatibilized with HDPE functionalized by ultraviolet irradiation

The mechanical properties of CaCO₃ filled high density polyethylene (HDPE) compatibilized with ultraviolet (UV) irradiated HDPE (uHDPE) were studied and the interfacial interactions between CaCO₃ and the polymers were evaluated by SEM, the Molau test, and ESCA. UV irradiation in air introduces the following functional groups on HDPE: >COOH, >C?O, ? OOH and ? OH. The concentration of these groups increases with irradiation time. The addition of a small amount (<10% by wt) of uHDPE to the HDPE/CaCO₃ improves the tensile and impact strength. For example, the addition of 3% HDPE irradiated for 500 hours (u500HDPE) increases the tensile and impact strength of HDPE/CaCO₃ from 16.7 MPa and 210 J/m to 25.2 MPa and 430 J/m, respectively. Chemical reactions between uHDPE and CaCO₃ promote interactions between HDPE and CaCO₃. The morphology of the compatibilized compound is nearly homogenous, and no CaCO₃ sediment was observed in a hot xylene solution of HDPE/u500HDPE/CaCO₃ when the content of u500HDPE exceeded 30% (wt).     

Effect of EPDM‐g‐MAH on the morphology and properties of PA6/EPDM/HDPE ternary blends

The formation of core‐shell morphology within the dispersed phase was studied for composite droplet polymer‐blend systems comprising a polyamide‐6 matrix, ethylene‐propylene‐diene terpolymer (EPDM) shell and high density polyethylene (HDPE) core. In this article, the effect of EPDM with different molecular weights on the morphology and properties of the blends were studied. To improve the compatibility of the ternary blends, EPDM was modified by grafting with maleic anhydride (EPDM‐g‐MAH). It was found that core‐shell morphology with EPDM‐g‐MAH as shell and HDPE as core and separated dispersion morphology of EPDM‐g‐MAH and HDPE phase were obtained separately in PA6 matrix with different molecular weights of EPDM‐g‐MAH in the blends. DSC measurement indicated that there may be some co‐crystals in the blends due to the formation of core‐shell structure. Mechanical tests showed that PA6/EPDM‐g‐MAH/HDPE ternary blends with the core‐shell morphology exhibited a remarkable rise in the elongation at break. With more perfect core‐shell composite droplets and co‐crystals, the impact strength of the ternary blends could be greatly increased to 51.38 kJ m^?2, almost 10 times higher than that of pure PA6 (5.50 kJ m^?2). POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Studies on fast functionalization of HDPE by ultraviolet irradiation and functionalized HDPE/CaCO3 composites

High density polyethylene (HDPE) was functionalized quickly by ultraviolet irradiated in ozone atmosphere. The oxygen-containing groups in the functionalized HDPE were C=O and C–O, and their content increased with increasing the irradiation time. The molecular weight of the functionalized HDPE decreased and its distribution became wider with increasing the irradiation time. The gel was not found in the functionalized HDPE. Compared with those of HDPE, the melting temperature and crystallinity of the functionalized HDPE decreased. With increasing the irradiation time, the hydrophilicity of the functionalized HDPE was enhanced, while its temperature of thermal decomposition decreased. The functionalized HDPE/CaCO₃ composites were prepared. Compared with those of HDPE/CaCO₃ composites, the compatibility and dispersion of the functionalized HDPE/CaCO₃ composites were enhanced observably. The tensile strength and notch impact strength of the functionalized HDPE/CaCO₃ composites increased with increasing the irradiation time.     

Mechanical,wear, and dielectric behavior of TiO2 reinforced high-density polyethylene composites

Almost fully dense high-density polyethylene (HDPE) reinforced with submicron-sized titanium dioxide (TiO₂) ceramic filler (up to 40 vol %) was fabricated using compression molding. More than 98.5% ρ_th (theoretical density) could be obtained for all the HDPE compositions and its measured density varied between 0.94 and 2.25 g cc⁻¹. The hardness of HDPE increased considerably from 32.6 to 69 MPa (i.e., by two times) with the addition of 40 vol % TiO₂. The compression strength (19.03–34.16 MPa) and modulus of elasticity (0.49–1.05 GPa) of HDPE were also found to increase with the addition of TiO₂ filler. However, the HDPE exhibited good ductility (59% strain) up to 20 vol % TiO₂ and it was reduced with the further addition of TiO₂. The strain decreased drastically to 7.6% for HDPE-40 vol % TiO₂. Addition of TiO₂ filler leads to a considerable decrease in wear rate and coefficient of friction (COF). The wear studies revealed that the HDPE-40% TiO₂ composite exhibited a low wear rate of 1.82 × 10⁻⁵ mm³ N m⁻¹ and COF of 0.13. The dielectric constant of HDPE (at 10 kHz) was also considerably increased from 5.31 to 20.02 with the addition of TiO₂ up to 40 vol %. Achievement of such high dielectric constant for HDPE materials is the highest ever reported for HDPE. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47610.     

HDPE/PC分散相纤维化及其原位复合材料的研究

将高密度聚乙烯(HDPE)和聚碳酸酯(PC)在双螺杆挤出机中熔融共混挤出，通过改变对挤出物施加的牵引速度，研究了拉伸力场对HDPE／PC共混物的形态及其原位复合材料性能的影响。结果表明，随着牵引速度的提高，纤维状分散相所占比例增加，但纤维直径无明显变化；HDPE／PC原位复合材料与其普通共混材料相比，拉伸强度基本无变化，但冲击强度提高较大。     

Effect of storage on ultraviolet irradiated HDPE

Abstract

Oxygen containing groups such as C=O and C–O were introduced onto high density polyethylene (HDPE) chains by ultraviolet (irradiated at 70°C and different light intensities in air). The contents of oxygen containing groups were unchanged after storage, indicating that these groups were stable in HDPE chains. The water contact angles of the irradiated HDPE at different light intensities after storage were equivalent to those of the irradiated HDPE before storage. Small quantity of the irradiated HDPE at different light intensities before and after storage as a compatibiliser were added into the HDPE/CaCO₃ composite respectively, and the HDPE/CaCO₃/irradiated HDPE before and after storage composite were prepared respectively. The tensile strength and the impact strength of HDPE/CaCO₃/irradiated HDPE after storage composite were similar to those of the HDPE/CaCO₃/irradiated HDPE before storage composite. The irradiated HDPE after storage was an efficacious compatibiliser.