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).     

Studies on high density polyethylene (HDPE) functionalized by ultraviolet irradiation and its application

The structure and properties of high density polyethylene (HDPE) functionalized by ultraviolet irradiation at different light intensities in air were studied by electron analysis, FTIR spectroscopy, contact angle with water, differential scanning calorimetry and mechanical properties measurement. The results show that oxygen‐containing groups such as C?O, C—O and C(?O)O were introduced onto the molecular chain of HDPE following irradiation, and the rate and efficiency of HDPE functionalization increased with enhancement of irradiation intensity. After irradiation, the melting temperature, contact angle with water and notched impact strength of HDPE decreased, the degree of crystallinity increased, and their variation amplitude increased with irradiation intensity. Compared with HDPE, the yield strength of HDPE irradiated at lower light intensity (32 W m^?2 and 45 W m^?2) increases monotonically with irradiation time, and the yield strength of HDPE irradiated at higher light intensity (78 W m^?2) increases up to 48 h and then decreased with further increase in irradiation time. The irradiated HDPE behaved as a compatibilizer in HDPE/polycarbonate (PC) blends, and the interface bonding between HDPE and PC was ameliorated. After adding 20 wt% HDPE irradiated at 78 W m^?2 irradiation intensity for 24 h to HDPE/PC blends, the tensile yield strength and notched Izod impact strength of the blend were increased from 26.3 MPa and 51 J m^?1 to 30.2 MPa and 158 J m^?1, respectively. Copyright © 2003 Society of Chemical Industry     

Studies on quick functionalization of polyethylene through ultraviolet irradiation and its composites

The oxygen-containing groups such as C–O, C=O, and C(=O)O were quickly introduced onto high-density polyethylene (HDPE) chains through ultraviolet irradiation in ozone atmosphere, and the functionalized HDPE was prepared. The content of the C–O, C=O, and C(=O)O groups increased with increasing the irradiation time. There was no gel in the functionalized HDPE. Compared with that of HDPE, the crystal form, cell parameters, and face space of the functionalized HDPE did not change, and its melting temperature and thermal stability decreased, while the crystallinity, hydrophilicity, and melt index increased. The functionalized HDPE/Sericite–Tridymite–Cristobalite (STC) (60/40) composite was prepared by melting blend. Compared with that of the HDPE/STC composite, the interfacial interaction and the dispersion of the STC particles in the functionalized HDPE/STC composite were improved markedly. With increasing the irradiation time, the tensile strength and notched impact strength of the functionalized HDPE/STC composite increased, while its melt index decreased.     

HDPE/POE/CaCO3三元体系薄膜研究

采用聚烯烃弹性体（POE）和重质碳酸钙对HDPE薄膜进行改性,研究了POE和重质碳酸钙的用量对共混体系薄膜力学性能、流变性能的影响。结果表明,POE的加入,使HDPE／POE薄膜的单位落镖冲击破损质量增加,而拉伸强度则有所下降。当POE的质量分数为10％时,薄膜的单位落镖冲击破损质量提高了51．1％,但薄膜的拉伸强度下降了20．5％。在HDPE／POE／CaC03体系中,当POE、重质碳酸钙的质量分数分别为10％和5％时,薄膜的单位落镖冲击强度比纯HDPE提高95．6％,且拉伸强度不降低。     

HDPE/CaCO3纳米复合材料的制备及性能

通过熔融共混法制备HDPE/纳米CaCO3复合材料,并通过TEM观察复合材料的微观结构.结果表明:纳米CaCO3基本以纳米级均匀分散在HDPE基体中,HDPE/纳米CaCO3复合材料的熔体指数比纯HDPE有所下降,并且当纳米CaCO3含量为5份时,复合材料的冲击强度提高约26.2%;而纳米CaCO3含量为3份时,复合材料的拉伸强度提高约2%,同时热分解温度比纯HDPE提高了49.8℃;热失重残余量在纳米CaCO3含量为8份时提高到了6.98%.     

滑石粉及CaCO3对HDPE的共复合研究

在反应性偶联剂及助偶联剂存在下,将CaCO3或滑石粉对高密度聚乙烯（HDPE）进行复合时,随复合粉体含量的增加,CaCO3复合体系表现为拉伸强度下降但冲击强度大幅度增加,滑石粉复合体系则表现为拉伸强度有较大的增加但冲击强度有较大的下降;将滑石粉和CaCO3进行共复合时,可以同时发挥片状滑石粉的增强作用和近球状CaCO3的增韧作用,得到综合力学性能较好的复合材料,但其配合比、粉体总添加量及助偶联剂添加量将对体系的力学性能产生较大的影响;各体系冲击断面的扫描电子显微镜照片所显示的微观形状和其力学物性有较好的对应,证明在共复合体系中,CaCO3既能通过偶联剂及助偶联剂的作用对HDPE产生较好的增韧效果,又能对滑石粉的分散起到一定的促进作用,使体系的拉伸强度有所提高。     

HDPE/CaCO3复合材料的力学和热性能

应用Instron材料试验机和Ceast冲击试验机于室温下测量碳酸钙填充高密度聚乙烯(HDPE)复合材料.随着填料质量分数(Φ)的增加,试样的拉伸模量和拉伸断裂能呈非线性增大;而拉伸屈服应力、拉伸强度和冲击断裂能则仅在Φ＝10%时稍大于未填充的HDPE.热重分析实验结果表明,试样的热分解温度随着Φ的增加而呈非线性函数形式增大.     

Polyethylene toughened by CaCO3 particle: Brittle-ductile transition of CaCO3-toughened HDPE

The dependencies of the notched Izod impact toughness of HDPE / CaCO₃ blends on CaCO₃ particle concentration and particle size are analyzed. It was found that the notched Izod impact strength (S) of HDPE / CaCO₃ blends depends discontinuously on CaCO₃ particle concentration. A brittle-ductile transition occurs when the CaCO₃ volume fraction (V_f) increases to a critical value (Vη_f). Furthermore, a brittle-ductile transition master curve can be constructed by taking the matrix ligament thickness (L) into account as a parameter instead of V_f. The results show that the critical matrix ligament thickness (L_c) is a single parameter for the transition and L_c = 5.2μm for HDPE / CaCO₃ blends. The impact strength, however, varies considerably with CaCO₃ particle size, which shows that CaCO₃ particle size is another dominating parametor for the toughness of HDPE / CaCO₃ blends. © 1993 John Wiley & Sons, Inc.     

母料法制备HDPE/POE/CaCO3薄膜的性能研究

采用母料法(二次挤出法)制备HDPF/POE/CaCO3共混物薄膜.比较了母料法与一次挤出法制得薄膜的力学性能与透光率.结果表明,在工艺参数相同时,母料法制备的薄膜力学性能比一次挤出法要好,而薄膜透光率基本相同.当POE、重质碳酸钙质量分数均为10%时,母料法制备的薄膜拉伸强度、断裂伸长率、单位冲击破损质量比纯HDPE薄膜分别提高了24.8%、27.5%、121%,比二次挤出法制备的薄膜力学性能分别提高了36.8%、14.1%、52.5%.     

Structure and properties of isotactic polypropylene functionalized by ultraviolet irradiation

The structural, crystalline, thermal, morphological, and mechanical properties of isotactic polypropylene (iPP) functionalized by lower energy ultraviolet (UV) irradiation are studied by means of infrared spectroscopy (IR), differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), thermogravimetry (TG), thermomechanical analysis (TMA), polariscope, and mechanical measurements. After the UV irradiation in less than a few hours, the oxygen containing polar groups have been introduced onto iPP chains. DSC analysis shows that a new melting peak is observed around 150°C for the UV irradiated iPP, indicating that there is a α‐phase to β‐phase transition during UV irradiation process. Under polariscope, the morphology of the UV irradiated iPP is changed, and the deformed α‐phase morphology can be observed. DSC and WAXD analysis reveal for the crystallinity of the UV‐irradiated iPP increase with UV time, but the relative level and the order of β‐phase increase and then decrease with increasing UV time. Under the controlled UV time, the thermomechanical deformation of iPP decrease, and the initial and final thermal degradation temperature of iPP rises up by 70 to 125°C higher, respectively, indicating that the UV‐irradiated iPP has higher thermal stability than the non‐UV irradiated iPP. The tensile and impact strength, the elongation at break, and the Young's modulus of the UV‐irradiated iPP are enhanced, exhibiting the toughened and strengthened effects. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1456–1466, 2001     

Preparation and properties of HDPE/CaCO3/OMMT ternary nanocomposite

A series of binary composites based on HDPE (high density polyethylene) and nanoinorganic particles such as nano‐CaCO₃ and OMMT (organic montmorillonite) were prepared. Their properties including tensile, impact strength, and some thermal properties were tested. The results showed that binary composite has partial improvement in mechanical properties compared with pure HDPE. A ternary composite nano‐CaCO₃/OMMT/HDPE was prepared and characterized. It was found that the mechanical and thermodynamic properties of this ternary composite have been enhanced greatly compared with both pure HDPE and binary composites. The tensile strength, Young's modulus, flexural strength, elastic modulus, and impact strength of nano‐CaCO₃/OMMT/HDPE were increased 124.6%, 302.7%, 73.86%, 58.97%, and 27.25%, respectively. The DMA test results showed that the mechanical properties of ternary composite were increased because of the limitation on the movement of HDPE due to inorganic particles. The synergistic effect introduced by nanoparticles may play an important role in all these processes. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

HDPE/UHMWPE/CaCO3复合材料流变学行为研究

利用高级流变扩展系统仪(ARES)分别对碳酸钙(CaCO3)填充高密度聚乙烯(HDPE),碳酸钙填充高密度聚乙烯(HDPE)/超高摩尔质量聚乙烯(UHMWPE)复合材料的流变学行为进行了研究.结果表明,不同的加工条件下,CaCO3对HDPE流变行为基本没有影响,而对HDPE/UHMWPE复合体系影响明显.随着转矩流变仪剪切速率的提高,HDPE/UHMWPE/CaCO3三元复合体系融体黏弹性参数发生改变.其中低频储能模量(G′)、损耗模量(G″)和零切黏度(η0)逐渐升高,损耗因子(tanδ)逐渐降低,表明体系融体流变行为由liquid-like行为向solid-like 行为转变,融体分子链作用加强.加工条件的改变引起了融体结构的转变,从而导致等温结晶过程加快.熔体黏弹性转变与CaCO3刚性颗粒与UHMWPE颗粒之间的相互作用密切相关.     

HDPE/LLDPE/CaCO3共混物注射成型收缩率的研究

研究了高密度聚乙烯（HDPE）／线性低密度聚乙烯（LLDPE）共混物及其碳酸钙（CaCO3）填充体系的注射成型收缩率,分别用示差扫描量热仪（DSC）和AR2000高级流变仪分析测定了共混物的结晶度和熔体黏度,并探讨了不同配比下共混物结晶度和熔体黏度与成型收缩率的关系。结果表明,在加工条件不变的情况下,HDPE／LLDPE共混物成型收缩率受结晶度和熔体黏度的显著影响。随LLDPE用量的增加,收缩率的变化明显分为三个阶段,先迅速增大,然后变化减缓,最后又逐渐减小。加入少量铝酸酯活化的CaCO3可以显著降低共混物的成型收缩率。     

HDPE／CaCO3复合材料片材制品的力学性能

通过制备不同含量的微米级和纳米级碳酸钙(CaCO3)填充的高密度聚乙烯(HDPE)片材制品,对其力学性能进行分析。研究了微米级和纳米级CaCO3对HDPECaCO3复合材料片材制品的力学性能的影响规律,并对此影响规律进行了合理的解释。     

基于收敛—发散流动的CaCO3/HDPE复合材料混合性能

设计可产生周期性收敛—发散流动的模头,使流动过程中物料受到周期性的压缩与膨胀作用,物料受到拉伸应力与剪切应力的复合应力作用,从而有利于提高混合效果;通过改变物料流经收敛板的次数可调整物料受到压缩与膨胀作用的停留时间。利用该模头在单螺杆挤出机上进行了CaCO3填充高密度聚乙烯(HDPE)熔融共混实验,并对复合材料进行宏观力学性能测试与微观结构表征,测试结果表明:收敛—发散流动能提高复合材料的力学性能,物料受到反复压缩与膨胀作用的停留时间对复合材料性能的提高有重要影响,当CaCO3含量高时需要较长时间的压缩与膨胀作用才能达到提高复合材料性能的目的;从复合材料断面的扫描电镜照片可以看出经收敛—发散流动作用后复合材料中CaCO3粒径更细,粒径分布更均匀。     

Mechanical properties of i-PP/CaCO3 composites

Tensile and impact behavior of CaCO₃-filled polypropylene was studied in the composition range 0–60 wt % filler. Tensile modulus increased while tensile strength and breaking elongation decreased with increase in CaCO₃ content. The modulus increase and elongation decrease were attributed to increased filler–polymer interaction resulting in reduction in molecular mobility, while increased amorphization and obstruction to stress transfer accounted for the tensile strength decrease. Analysis of tensile strength data showed introduction of stress concentration in the composites. Izod impact strength at first increased up to a critical CaCO₃ content, beyond which the value decreased. Surface treatment of CaCO₃ with a titanate coupling agent LICA 12 enhances the adhesion of the filler and polymer, which further modifies the strength properties. Scanning electron microscopic studies indicated better dispersion of CaCO₃ particles upon surface treatment, which effected the changes in the strength properties of the composites.     

Toughness of HDPE/CaCO3 microcomposites prepared from masterbatch by melt blend method

In this study, a series of high‐density polyethylene and micro/nanocalcium carbonate polymer composites (HDPE/CaCO₃ nanocomposites) were prepared via melt blend technique using a twin screw extruder. Nanocomposite samples were prepared via injection molding for further testing. The effect of % loading of CaCO₃ on mechanical and fracture toughness of these composites has been investigated in details. The effect of precrack length variation on the fracture toughness of the composite samples was evaluated, and the morphology of the fractured samples was also observed using scanning electron microscopy (SEM). It was found that increasing the % of CaCO₃ and precrack length decreased the fracture toughness. Fracture surface examination by SEM indicated that the diminished fracture properties in the composites were caused by the aglomerization of CaCO₃ particles which acted as stress concentrators. A finite element analysis using ANSYS was also carried out to understand the effect of agglomeration size, interaction between the particles and crack tip length on the fracture properties of these composites. Finally, a schematic presentation of the envisioned fracture processes was proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of strain rate on the toughening effect of CaCO3 in polypropylene/CaCO3 composites

The effects of 40 and 50 wt% of calcium carbonate on the mechanical properties of polypropylene were investigated by uniaxial tensile deformation at room temperature and at loading rates of 5, 50, and 125 mm/min. The results showed that the addition of calcium carbonate to polypropylene decreased yield strength while increasing modulus. The decreases yield strength was attributed to the poor adhesion between filler and matrix. The tensile toughness of polypropylene was improved by the addition of calcium carbonate particles at constant strain rate because of the plastic deformation of interparticle ligaments following particle‐matrix debonding. The (strain rate) sensitive behavior of the composites (at constant calcium carbonate content) was observed. J. VINYL ADDIT. TECHNOL., 19:271–275, 2013. © 2013 Society of Plastics Engineers     

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.     

A study on HDPE/sulfonated EPDM‐treated CaCO3 blends

In this article, sulfonated ethylene‐propylene‐diene monomer terpolymer (H–SEPDM) was used to treat CaCO₃ particles. CaCO₃ particles are encapsulated by H–SEPDM through the reaction of sulfonic acid group (? SO₃H) in H–SEPDM with CaCO₃ to improve the interface adhesion of CaCO₃ with HDPE. In case the treated CaCO₃ is blended with HDPE, a brittle–ductile transition occurs. The impact strength of the blend rises sharply at 25–30 wt % CaCO₃, and amounts to more than 700 J/m, four times as high as that of HDPE at 30 wt % CaCO₃, without much loss of its yield strength and modulus. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2140–2144, 2001