共查询到20条相似文献,搜索用时 781 毫秒
1.
2.
3.
用DSC和WAXD方法研究了高密度聚乙烯/聚(乙烯丙烯辛烯-1)(HDPE/EPO)共混体系的结晶性能。共混物的DSC曲线皆呈单峰,表明共混体系形成了共晶。晶胞参数a及结晶度随共混物组成而变,进一步证明HDPE/EPO共混体系的相容性。 相似文献
4.
5.
6.
7.
8.
线性低密度聚乙烯/乙烯醋酸乙烯共聚物共混体系的相容性及性能杨毓华*白春霞花荣于李三喜(中国科学院长春应用化学研究所长春130022)(沈阳化工学院高分子科学与工程系沈阳)关键词线性低密度聚乙烯,乙烯醋酸乙烯共聚物,共混,相容性,DSC,WAXD,力... 相似文献
9.
10.
11.
12.
Thermoplastic elastomer (TPE) comprising air‐dried sheet or natural rubber (ADS or NR) and high‐density polyethylene (HDPE) was prepared by a simple blending technique. NR and HDPE were mixed with each type of phenolic compatibilizer (HRJ‐10518 or SP‐1045) or liquid natural rubber (LNR) at 180°C in an internal mixer. The mixing torque, shear stress, and shear viscosity of the blends increased with increasing amounts of NR. Positive deviation blend (PDB) for the blends containing active hydroxyl methyl phenolic resin in HRJ‐10518 or dimethyl phenolic resin in SP‐1045 was obtained. PDB was not observed for the blends without the compatibilizers or with LNR. The blends with HRJ‐10518 or SP‐1045 were compatible or partially compatible while the LNR blends were incompatible. In the phenolic compatibilized blends, NR dispersed in the HDPE matrix was found in the NR/HDPE blends of 20/80, 40/60, and 50/50 ratios. HDPE dispersed in NR matrix was obtained in the NR/HDPE blend of 80/20 ratio, and the co‐continuous phase was accomplished in the NR/HDPE blend of 60/40 ratio. The NR/HDPE blend at 60/40 ratio compatibilized with HRJ‐10518 and fabricated by a simple plastic injection molding machine exhibited higher ultimate tensile strength and elongation at break (EB). Incorporation of parafinic oil caused a decreasing tendency in tensile strength with increases in EB. The TPNRs exhibited high elastomeric nature with low‐tension set. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
13.
Inorganic filler manufactured for incorporation into thermoplastic elastomers usually are surface treated with organic reagents in order to improve the interfacial adhesion between filler and the matrix. In the present paper, the effects of acrylic acid (AA) on tensile and morphology properties of wollastonite (WS) filled high density polyethylene (HDPE)/Natural Rubber (NR) composites were studied. The untreated and treated HDPE/NR/WS composites were melt-blending at 180 °C with rotor speed of 50 rpm for 10 minutes. The composites were tensile-tested according to ASTM D638 and the etched surfaces were observed using scanning electron microscope (SEM). Tensile strength and elongation at break of the compositesdecreased upon the addition of wollastonite, but Young's modulus improves. The results of this study showed that the treated composites are found to have better tensile properties than the untreated composites. The morphology of treated composite showed better interfacial interaction between HDPE/NR and wollastonite. 相似文献
14.
Several techniques of polymer characterization and different ageing methods have been used with the aim of developing a simple, fast and reliable method to qualify commercial pipe-grade polyethylene samples, and possibly to evidence the presence of recycled PE within PE pipes. The results of the different techniques used have been compared with respect to their capability to evidence differences in the degradation rate of different HDPE samples (including virgin HDPE, HDPE pipes obtained from virgin HDPE and HDPE pipes that probably contain recycled HDPE). FT-IR, TGA and DSC were found unsuitable for this purpose but, on the contrary, MFI measurements have been found sensitive enough to evidence different degradation rates when a suitable combination of high temperature, oxygen, mechanical stresses and mixing time had been used for ageing the sample. 相似文献
15.
Liping Zhao Zhenhu Cao Zhengping Fang Zhenghong Guo 《Journal of Thermal Analysis and Calorimetry》2013,114(3):1287-1294
The influence of fullerene (C60) on the thermal and thermal-oxidative degradation of high-density polyethylene (HDPE) was studied using non-isothermal thermogravimetric analysis under nitrogen (N2) and air atmosphere. Kinetic parameters of the degradation were evaluated using the Flynn–Wall–Ozawa method, which does not require the knowledge of the reaction mechanism. The results showed that the addition of C60 enhanced the thermal stability of HDPE and increased the activation energy both in N2 and air atmosphere and especially affected the initial stage of degradation. In N2, C60-trapped carbon-centered radical originated from the degradation of HDPE to improve the thermal stability and increase the activation energy. While in air, C60 trapped the alkyl radicals and alkyl peroxide radicals to inhibit the hydrogen abstraction (especially the initial stage of thermo-oxidative degradation) and form more stable species, which improved the thermal stability and increased the activation energy during the thermal degradation of HDPE. Comparing with that of pure HDPE, the changes of activation energy for HDPE/C60 nanocomposites were higher in air than in N2, especially in the initial stage. 相似文献
16.
A study has been made of the effect of orientation on the oxidative degradation of poly(vinylchloride) (PVC), low density polyethylene (LDPE) and high density polyethylene (HDPE) under the influence of γ- and u.v.-radiation. The effect of drawing in PVC is to increase the rate of oxidative degradation; in LDPE and HDPE, this rate decreases (especially for HDPE) both under u.v. and γ-radiation. 相似文献
17.
《Journal of Analytical and Applied Pyrolysis》2011,90(2):313-317
The present work is aimed at recycling plastic wastes economically and efficiently, for which pure high density polyethylene (HDPE) has been initially selected for the investigations. Thermogravimetric technique has been used to investigate, analyze and compare the thermal and catalytic degradation of HDPE. The catalytic degradation was investigated over the medium pore silicoaluminophosphate, SAPO-11 molecular sieve. The thermogravimetric evaluation was performed using 2–30 wt% catalyst, and the apparent activation energies for the thermal and catalytic polymer degradation were estimated using various iso-conversional methods. The apparent activation energy was found to be lower when SAPO-11 was used compared to the direct thermal degradation of HDPE. The activation energy and coke levels are comparable to the medium pore zeolite ZSM-5 and lower than the values obtained over large pore zeolites reported in literature. 相似文献
18.
19.
H.-S. Kim H.-S. Yang H.-J. Kim H.-J. Park 《Journal of Thermal Analysis and Calorimetry》2004,76(2):395-404
The thermal degradation and thermal stability of rice husk flour (RHF) filled polypropylene (PP) and high-density polyethylene
(HDPE) composites in a nitrogen atmosphere were studied using thermogravimetric analysis. The thermal stability of pure PP
and HDPE was found to be higher than that of wood flour (WF) and RHF. As the content of RHF increased, the thermal stability
of the composites decreased and the ash content increased. The activation energy of the RHF filled PP composites increased
slowly in the initial stage until α=0.3 (30% of thermal degradation region) and thereafter remained almost constant, whereas
that of the RHF filled HDPE composites decreased at between 30 and 40 mass% of RHF content. The activation energy of the composites
was found to depend on the dispersion and interfacial adhesion of RHF in the PP and HDPE matrix polymers.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Telmo Ojeda Ana FreitasKátia Birck Emilene DalmolinRodrigo Jacques Fátima BentoFlávio Camargo 《Polymer Degradation and Stability》2011,96(4):703-707
High density polyethylene (HDPE), linear low density polyethylene (LLDPE), and isotactic polypropylene (PP) containing antioxidant additives at low or zero levels were extruded and blown moulded as films. An HDPE/LLDPE commercial blend containing a pro-oxidant additive (i.e., an oxo-biodegradable blend) was taken from the market as supermarket bag. These four polyolefin samples were exposed to natural weathering for one year during which their structure and thermal and mechanical properties were monitored. This study shows that the real durability of olefin polymers may be much shorter than centuries, as in less than one year the mechanical properties of all samples decreased virtually to zero, as a consequence of severe oxidative degradation, that resulted in substantial reduction in molar mass accompanied by a significant increase in content of carbonyl groups. PP and the oxo-bio HDPE/LLDPE blend degraded very rapidly, whereas HDPE and LLDPE degraded more slowly, but significantly in a few months. The main factors influencing the degradability were the frequency of tertiary carbon atoms in the chain and the presence of a pro-oxidant additive. The primary (sterically hindered phenol) and secondary (phosphite) antioxidant additives added to PP slowed but did not prevent rapid photo-oxidative degradation, and in HDPE and LLDPE the secondary antioxidant additive had little influence on the rate of abiotic degradation at the concentrations used here. 相似文献