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1.
Alireza Ashori 《Journal of Polymers and the Environment》2010,18(1):65-70
Hybrid composites of thermoplastic biofiber reinforced with waste newspaper fiber (NF) and poplar wood flour (WF) were prepared.
The weight ratio of the lignocellulosic materials to polymer was 30:70 (w:w). Polypropylene (PP) and maleic anhydride grafted
polypropylene (MAPP) were also used as the polymer matrix and coupling agent, respectively. The mechanical properties, morphology
and thermal properties were investigated. The obtained results showed that tensile and flexural modulus of the composites
were significantly enhanced with addition of biofibers in both types (fiber and flour), as compared with pure PP. However,
the increasing in WF content substantially reduced the tensile, flexural and impact modulus, but improved the thermal stability.
This effect is explained by variations in fiber morphological properties and thermal degradation. Increasing fiber aspect
ratio improved mechanical properties. The effect of fiber size on impact was minimal compared to the effects of fiber content.
Scanning electron microscopy has shown that the composite, with coupling agent, promotes better fiber–matrix interaction.
The largest improvement on the thermal stability of hybrid composites was achieved when WF was added more. In all cases, the
degradation temperatures shifted to higher values after addition of MAPP. This work clearly showed that biofiber materials
in both forms of fiber and flour could be effectively used as reinforcing elements in thermoplastic PP matrix. 相似文献
2.
Maria T. B. Pimenta Antonio J. F. Carvalho Fabiola Vilaseca Jordi Girones Joan P. López Pere Mutjé Antonio A. S. Curvelo 《Journal of Polymers and the Environment》2008,16(1):35-39
Treated sisal fibers were used as reinforcement of polypropylene (PP) composites, with maleic anhydride-grafted PP (MAPP)
as coupling agent. The composites were made by melting processing of PP with the fiber in a heated roller followed by multiple
extrusions in a single-screw extruder. Injection molded specimens were produced for the characterization of the material.
In order to improve the adhesion between fiber and matrix and to eliminate odorous substances, sisal fibers were treated with
boiling water and with NaOH solutions at 3 and 10 wt.%. The mechanical properties of the composites were assessed by tensile,
bend and impact tests. Additionally, the morphology of the composites and the adhesion at he fiber–matrix interface were analyzed
by SEM. The fiber treatment led to very light and odorless materials, with yields of 95, 74 and 62 wt.% for treatments with
hot water, 3 and 10 wt.% soda solution respectively. Fiber treatment caused an appreciable change in fiber characteristics,
yet the mechanical properties under tensile and flexural tests were not influenced by that treatment. Only the impact strength
increased in the composites with alkali-treated sisal fibers. 相似文献
3.
Elisângela Corradini Syed H. Imam José A. M. Agnelli Luiz H. C. Mattoso 《Journal of Polymers and the Environment》2009,17(1):1-9
Coconut, sisal and jute fibers were added as reinforcement materials in a biodegradable polymer matrix comprised of starch/gluten/glycerol.
The content of fibers used in the composites varied from 5% to 30% by weight of the total polymers (starch and gluten). Materials
were processed in a Haake torque rheometer (120 °C, 50 rpm) for 6 min. The mixtures obtained were molded by heat compression
and further characterized. Addition of lignocellulosic fibers in the matrix decreased the water absorption at equilibrium.
The diffusion coefficient decreased sharply around 5% fiber concentration, and further fiber additions caused only small variations.
The thermogravimetric (TG) analysis revealed improved thermal stability of matrix upon addition of fibers. The Young’s modulus
and ultimate tensile strength increased with fiber content in the matrix. The storage modulus increased with increasing fiber
content, whereas tanδ curves decreased, confirming the reinforcing effect of the fibers. Morphology of the composites analyzed
under the scanning electron microscope (SEM) exhibited good interfacial adhesion between the matrix and the added fibers.
Matrix degraded rapidly in compost, and addition of increased amounts of coconut fiber in the matrix caused a slowdown the
biodegradability of the matrix.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may be
suitable. 相似文献
4.
Jutarat Prachayawarakorn Pornnipa Ruttanabus Pimvilai Boonsom 《Journal of Polymers and the Environment》2011,19(1):274-282
Biodegradable polymer was prepared as thermoplastic starch (TPS) using rice and waxy rice starches. In order to increase mechanical
properties and reduce water absorption of the TPS, cotton fiber was incorporated as the fiber reinforcement into the TPS matrix.
The effect of cotton fiber contents and lengths on properties of the TPS was examined. Internal mixer and compression molding
machine were used to mix and shape the samples. It was found that the thermoplastic rice starch (TPRS) showed higher stress
at maximum load and Young’s modulus but lower strain at maximum load than the thermoplastic waxy rice starch (TPWRS). In addition,
stress at maximum load and Young’s modulus of both TPRS and TPWRS increased significantly with the addition of the cotton
fiber. Cotton fiber contents and lengths also affected mechanical properties of the TPRS and TPWRS composites. Moreover, water
absorption of the TPRS and TPWRS composites decreased by the use of the cotton fibers. FT-IR and XRD techniques were used
to study a change in functional group and crystallinity of the thermoplastic starch composites. Morphological, thermal and
biodegradable properties of different thermoplastic starch composites were also investigated. 相似文献
5.
Effect of Orientation on the Morphology and Mechanical Properties of PLA/Starch Composite Filaments 总被引:1,自引:0,他引:1
Randal L. Shogren Gordon Selling J. L. Willett 《Journal of Polymers and the Environment》2011,19(2):329-334
Polylactic acid (PLA)/starch fibers were produced by twin screw extrusion of PLA with granular or gelatinized starch/glycerol
followed by drawing through a set of winders with an intermediate oven. At 30% starch, fibers drawn 2–5x were highly flexible
(elongation 20–100%) while undrawn filaments were brittle (elongation 2–9%). Tensile strength and moduli increased with increasing
draw ratio but decreased with increasing starch content. Mechanical properties were better for composites made with gelatinized
starch/glycerol than granular starch. In conclusion, orientation greatly increases the flexibility of PLA/starch composites
and this may be useful not only in fibers but also possibly in molded articles. Other advantages of starch addition could
include fiber softness without added plasticizer, moisture/odor absorbency and as a carrier for active compounds. 相似文献
6.
Sustainable Bio-Composites from Renewable Resources: Opportunities and Challenges in the Green Materials World 总被引:28,自引:0,他引:28
Sustainability, industrial ecology, eco-efficiency, and green chemistry are guiding the development of the next generation of materials, products, and processes. Biodegradable plastics and bio-based polymer products based on annually renewable agricultural and biomass feedstock can form the basis for a portfolio of sustainable, eco-efficient products that can compete and capture markets currently dominated by products based exclusively on petroleum feedstock. Natural/Biofiber composites (Bio-Composites) are emerging as a viable alternative to glass fiber reinforced composites especially in automotive and building product applications. The combination of biofibers such as kenaf, hemp, flax, jute, henequen, pineapple leaf fiber, and sisal with polymer matrices from both nonrenewable and renewable resources to produce composite materials that are competitive with synthetic composites requires special attention, i.e., biofiber–matrix interface and novel processing. Natural fiber–reinforced polypropylene composites have attained commercial attraction in automotive industries. Natural fiber—polypropylene or natural fiber—polyester composites are not sufficiently eco-friendly because of the petroleum-based source and the nonbiodegradable nature of the polymer matrix. Using natural fibers with polymers based on renewable resources will allow many environmental issues to be solved. By embedding biofibers with renewable resource–based biopolymers such as cellulosic plastics; polylactides; starch plastics; polyhydroxyalkanoates (bacterial polyesters); and soy-based plastics, the so-called green bio-composites are continuously being developed. 相似文献
7.
Biodegradable Polyester-Based Blend Reinforced with Curauá Fiber: Thermal,Mechanical and Biodegradation Behaviour 总被引:1,自引:1,他引:0
Fernanda Harnnecker Derval dos Santos Rosa Denise Maria Lenz 《Journal of Polymers and the Environment》2012,20(1):237-244
Biodegradable composites can be produced by the combination of biodegradable polymers (BP) as matrix and vegetal fibers as
reinforcement. Composites of a commercial biodegradable polymer blend and curauá fibers (loaded at 5, 15 and 20 wt%) were
prepared by melt mixing in a twin-screw extruder. Chemical treatments such as alkali treatment of the fiber and addition of
maleic anhydride grafted polypropylene (MA-g-PP) as coupling agent were performed to promote polymer/fiber interfacial adhesion so that mechanical performance can be
improved. The resulting composites were evaluated through hardness, melt flow index and tensile, flexural and impact strengths
as well as water absorption. Thermal analysis and Fourier transform infrared spectroscopy were also employed to characterize
the composites. The polymer/fiber interface was investigated through scanning electron microscopy analysis. The biodegradability
of composites was evaluated by compost-soil burial test. The addition of curauá fiber promoted an increase in the mechanical
strengths and composites treated with 2 wt% MA-g-PP with 20 wt% curauá fiber showed an increase of nearly 75% in tensile and 56% in flexural strengths besides an improvement
in impact strength with respect to neat polymer blend. Nevertheless, treated composites showed an increase in water absorption
and biodegradation tests showed that the addition of fiber retards degradation time. The retained mass of BP/20 wt% fiber
composite with MA-g-PP and neat BP was 68 and 26%, respectively, after 210 days of degradation test. 相似文献
8.
Jonn A. Foulk Wayne Y. Chao Danny E. Akin Roy B. Dodd Patricia A. Layton 《Journal of Polymers and the Environment》2006,14(1):15-25
Manufacturing composites with polymers and natural fibers has traditionally been performed using chopped fibers or a non-woven mat for reinforcement. Fibers from flax (Linum usitatissimum L.) are stiff and strong and can be processed into a yarn and then manufactured into a fabric for composite formation. Fabric directly impacts the composite because it contains various fiber types via fiber or yarn blending, fiber length is often longer due to requirements in yarn formation, and it controls the fiber alignment via weaving. Composites created with cotton and flax-containing commercial fabrics and recycled high-density polyethylene (HDPE) were evaluated for physical and mechanical properties. Flax fiber/recycled HDPE composites were easily prepared through compression molding using a textile preform. This method takes advantage of maintaining cotton and flax fiber lengths that are formed into a yarn (a continuous package of short fibers) and oriented in a bidirectional woven fabric. Fabrics were treated with maleic anhydride, silane, enzyme, or adding maleic anhydride grafted polyethylene (MAA-PE; MDEX 102-1, Exxelor® VA 1840) to promote interactions between polymer and fibers. Straight and strong flax fibers present problems because they are not bound as tightly within yarns producing weaker and less elastic yarns that contain larger diameter variations. As the blend percentage and mass of flax fibers increases the fabric strength, and elongation generally decrease in value. Compared to recycled HDPE, mechanical properties of composite materials (containing biodegradable and renewable resources) demonstrated significant increases in tensile strength (1.4–3.2 times stronger) and modulus of elasticity (1.4–2.3 times larger). Additional research is needed to improve composite binding characteristics by allowing the stronger flax fibers in fabric to carry the composites load. 相似文献
9.
Amnuay Wattanakornsiri Katavut Pachana Supranee Kaewpirom Matteo Traina Claudio Migliaresi 《Journal of Polymers and the Environment》2012,20(3):801-809
Green composites obtained from biodegradable renewable resources have gained much attention due to environmental problems resulting from conventionally synthetic plastics and a global increasing demand for alternatives to fossil resources. In this work we used different cellulose fibers from used office paper and newspaper as reinforcement for thermoplastic starch (TPS) in order to improve their poor mechanical, thermal and water resistance properties. These composites were prepared by using tapioca starch plasticized by glycerol (30 % wt/wt of glycerol to starch) as matrix reinforced by the extracted cellulose fibers with the contents ranging from 0 to 8 % (wt/wt of fibers to matrix). Properties of composites were determined by mechanical tensile tests, differential scanning calorimetry, thermogravimetric analysis, water absorption measurements, scanning electron microscopy, and soil burial tests. The results showed that the introduction of either office paper or newspaper cellulose fibers caused the improvement of tensile strength and elastic modulus, thermal stability, and water resistance for composites when compared to the non-reinforced TPS. Scanning electron microscopy showed a good adhesion between matrix and fibers. Moreover, the composites biological degraded completely after 8 weeks but required a longer time compared to the non-reinforced TPS. The results indicated that these green composites could be utilized as commodity plastics being strong, inexpensive, plentiful and recyclable. 相似文献
10.
The structure and properties of chicken feather barbs makes them unique fibers preferable for several applications. The presence
of hollow honeycomb structures, their low density, high flexibility and possible structural interaction with other fibers
when made into products such as textiles provides them unique properties unlike any other natural or synthetic fibers. No
literature is available on the physical structure and tensile properties of chicken feather barbs. In this study, we report
the physical and morphological structure and the properties of chicken feather barbs for potential use as natural protein
fibers. The morphological structure of chicken feather barbs is similar to that of the rachis but the physical structure of
the protein crystals in chicken feather barbs is different than that reported for feather rachis keratin. The tensile properties
of barbs in terms of their strength and modulus are similar but the elongation is lower than that of wool. Using the cheap
and abundant feathers as protein fibers will conserve the energy, benefit the environment and also make the fiber industry
more sustainable 相似文献
11.
Reactively Compatibilized Cellulosic Polylactide Microcomposites 总被引:3,自引:0,他引:3
Birgit Braun John R. Dorgan Daniel M. Knauss 《Journal of Polymers and the Environment》2006,14(1):49-58
Poly(lactic acid) (PLA) possesses a suite of favorable material properties that are enabling its penetration into diverse
markets (e.g., as packaging material or textile fibers). In order to increase the range of applications for this material,
it is necessary to modify its properties and for certain applications, reduce its cost. The introduction of fibers into a
polymeric matrix is an established route towards property enhancement provided good dispersion and intimate interfacial adhesion
can be achieved. In addition, cellulosic microfibers are obtainable at low to moderate cost. In this study, reactive compatibilization
of cellulosic fibers with PLA is pursued. Hydroxyl groups available on the surface of cellulosic fibers are used to initiate
lactide polymerization. Various processing strategies are investigated: (1) blending preformed PLA with the fiber material,
(2) through a one-step process in which lactide is polymerized in the presence of the fibers alone, or (3) reactive compatibilization
in the presence of preformed high molecular weight polymer. The results show that materials prepared by simultaneous introduction
of lactide and preformed high molecular PLA at the beginning of the reaction possess superior mechanical properties compared
to composites made by either purely mechanical mixing or solely polymerization of lactide in the presence of fibers. The modulus
of materials containing 25% fibers which are prepared by reactive compatibilization of 30% preformed PLA and 70% lactide (30/70
P/L) improves by 53% compared to the homopolymer, whereas 36% reinforcement can be achieved upon purely mechanical mixing.
A further increase to 35% fiber loading leads to a reduction in modulus due to an excess in initiating groups. The same trend
was observed in systems containing 65% preformed PLA and 35% lactide (65/35 P/L) with an overall achievable reinforcement
that was slightly lower. 相似文献
12.
Natural cellulosic fibers are one of the smartest materials for use as reinforcement in polymers possessing a number of applications. Keeping in mind the immense advantages of the natural fibers, in present work synthesis of natural cellulosic fibers reinforced polymer composites through compression molding technique have been reported. Scanning Electron microscopy (SEM), Thermo gravimetric/Differential thermal/Derivative Thermogravimetry (TGA/DTA/DTG), absorption in different solvents, moisture absorbance, water uptake and chemical resistance measurements were used as characterization techniques for evaluating the different behaviour of cellulosic natural fibers reinforced polymer composites. Effect of fiber loading on mechanical properties like tensile strength, flexural strength, compressive strength and wear resistances has also been determined. Reinforcing of the polymer matrix with natural fibers was done in the form of short fiber. Present work indicates that green composites can be successfully fabricated with useful mechanical properties. These composites may be used in secondary structural applications in automotive, housing etc. 相似文献
13.
Long Jiang Jijun Huang Jun Qian Feng Chen Jinwen Zhang Michael P. Wolcott Yawei Zhu 《Journal of Polymers and the Environment》2008,16(2):83-93
In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber (BPF) composites were prepared by melt compounding and injection molding. The
crystallization ability, tensile strength and modulus, flexural strength and modulus, and impact strength were found substantially
increased by the addition of BPF. Tensile and flexural elongations were also moderately increased at low fiber contents (<20%).
BPF demonstrated not only higher strength and modulus, but also higher failure strain than the PHBV8 matrix. Boron nitride
(BN) was also investigated as a nucleation agent for PHBV8 and maleic anhydride grafted PHBV8 (MA-PHBV8) as a compatibilizer
for the composite system. BN was found to increase the overall properties of the neat polymer and the composites due to refined
crystalline structures. MA-PHBV8 improved polymer/fiber interactions and therefore resulted in increased strength and modulus.
However, the toughness of the composites was substantially reduced due to the hindrance to fiber pullout, a major energy dissipation
source during the composite deformation. 相似文献
14.
This paper investigates and compares the performances of polylactic acid (PLA)/kenaf (PLA-K) and PLA/rice husk (PLA-RH) composites
in terms of biodegradability, mechanical and thermal properties. Composites with natural fiber weight content of 20% with
fiber sizes of less than 100 μm were produced for testing and characterization. A twin-screw extrusion was used to compound
PLA and natural fibers, and extruded composites were injection molded to test samples. Flexural and Izod impact test, TGA,
soil burial test and SEM were used to investigate properties. All results were compared to a pure PLA matrix sample. The flexural
modulus of the PLA increased with the addition of natural fibers, while the flexural strength decreased. The highest impact
strength (34 J m−1), flexural modulus (4.5 GPa) and flexural strength (90 MPa) were obtained for the composite made of PLA/kenaf (PLA-K), which
means kenaf natural fibers are potential to be used as an alternative filler to enhance mechanical properties. On the other
hand PLA-RH composite exhibits lower mechanical properties. The impact strength of PLA has decreased when filled with natural
fibers; this decrease is more pronounced in the PLA-RH composite. In terms of thermal stability it has been found that the
addition of natural fibers decreased the thermal stability of virgin PLA and the decrement was more prominent in the PLA-RH
composite. Biodegradability of the composites slightly increased and reached 1.2 and 0.8% for PLA-K and PLA-RH respectively
for a period of 90 days. SEM micrographs showed poor interfacial between the polymer matrix and natural fibers. 相似文献
15.
Growing interest in green products has provided fresh impetus to the research in the field of renewable materials. Plant fibers are not only renewable but also light in weight and low in cost. Polymer composites manufactured using them find applications in diverse fields such as automobiles, housing, and furniture. However, their hydrophilic nature and inadequate adhesion with matrix limits their use in high performance applications. In this study, a novel method for improving adhesion characteristics of natural fibers has been developed. This method is carried out by treating hemp fibers with a fungus: Ophiostoma ulmi, obtained from elm tree infected with Dutch elm disease. Treated fibers showed improved acid–base characteristics and resistance to moisture. Improved acid–base interactions between fiber and resin are expected to improve the interfacial adhesion, whereas improved moisture resistance would benefit the durability of the composites. Finally, composites were prepared using untreated/treated fibers and unsaturated polyester resin. Composites with treated fibers showed slightly better mechanical properties, which is most probably due to improved interfacial adhesion. 相似文献
16.
A. Venu Nadhan A. Varada Rajulu R. Li C. Jie L. Zhang 《Journal of Polymers and the Environment》2012,20(2):454-458
Green composites of regenerated cellulose short fibers/cellulose were prepared by dissolving cellulose in a green solvent of 7% NaOH/12% Urea aqueous solution that was pre cooled at ?12?°C. The effect of fiber loading on the tensile, optical, thermal degradation and cell viability was studied. The tensile properties of cellulose were improved by the regenerated cellulose fiber reinforcement. The interfacial bonding between the fibers and matrix was assessed using the fractographs and found it to be good. 相似文献
17.
Three to four billion pounds of chicken feathers are wasted in the United States annually. These feathers pose an environmental
challenge. In order to find a commercial application of these otherwise wasted feathers, composites have been prepared from
feathers. Flexural, impact resistance, and sound dampening properties of composites from chicken feather fiber (FF) and High
Density Polyethylene/Polypropylene (HDPE/PP) fiber have been investigated and compared with pulverized chicken quill-HDPE/PP,
and jute-HDPE/PP composites. Sound dampening by FF composites was 125% higher than jute and similar to quill although mechanical
properties were inferior to the latter two. In ground form, FF and jute composite properties were similar except for 34% higher
modulus of jute; under the same formulation and processing conditions, ground FF composites had nearly 50% lower mechanical
properties compared with ground quill composites. It was found that voids and density of composites have effect on mechanical
and sound dampening properties; however, no direct relationship was found between mechanical properties and sound dampening. 相似文献
18.
High density polyethylene (HDPE)/bamboo composites with different nanoclay and maleated polyethylene (MAPE) contents were
fabricated by melt compounding. The compounding characteristics, clay dispersion, HDPE crystallization, and mechanical properties
of the composites were studied. The equilibrium torque during compounding decreased with use of clay masterbatch and increased
with the addition of MAPE. The X-ray diffraction (XRD) data showed that the clay was exfoliated only when 1% clay was added
to pure HDPE without MAPE. For HDPE/bamboo systems, MAPE was necessary to achieve clay exfoliation. For pure HDPE system,
both dynamic and static bending moduli increased, while impact strength decreased with increased clay loading. For the HDPE/bamboo
fiber composites, tensile strength, bending modulus and strength were improved with the use of MAPE. The use of the clay in
the system led to reduced mechanical properties. Techniques such as pre-coating fibers with clay–MAPE mixture are needed to
enhance the synergetic effect of the clay and bamboo fiber on the composite properties in the future study. 相似文献
19.
Processing and characterization of a new biodegradable composite made of a PHB/V matrix and regenerated cellulosic fibers 总被引:1,自引:0,他引:1
Ch. Bourban E. Karamuk M. J. de Fondaumière K. Ruffieux J. Mayer E. Wintermantel 《Journal of Polymers and the Environment》1997,5(3):159-166
In this study, a biodegradable composite consisting of a degradable continuous cellulosic fiber and a degradable polymer matrix—poly(3-hydroxybutyrate)-co-poly(3-hydroxyvalerate
(PHB/V with 19% HV)—was developed. The composite was processed by impregnating the cellulosic fibers on-line withPHB/V powder in a fluidization chamber. The impregnated roving was then filament wound on a plate and hot-pressed. The resulting
unidirectional composite plates were mechanically tested and optically characterized by SEM. The fiber content was 9.9 ±0.9
vol% by volumetric determination. The fiber content predicted by the rule of mixture for unidirectional composites was 13.8
±1.4 vol%. Optical characterization showed that the fiber distribution was homogeneous and a satisfactory wetting of the fibers
by the matrix was achieved. Using a blower to remove excess matrix powder during processing increased the fiber content to
26.5 ±3.3 vol % (volumetric) or 30.0 ±0.4 vol% (rule of mixture). The tensile strength of the composite parallel to the fiber
direction was 128 ±12 MPa (10 vol% fiber) up to 278 ±48 MPa (26.5 vol% fiber), compared to 20 MPa for the PHB/V matrix. The
Young’s modulus was 5.8 ±0.5 GPa (10 vol% fiber) and reached 11.4 ±0.14 GPa (26.5 vol% fiber), versus 1 GPa for the matrix. 相似文献
20.
Merlin Aydın Hale Tozlu Sebnem Kemaloglu Ayse Aytac Guralp Ozkoc 《Journal of Polymers and the Environment》2011,19(1):11-17
In this study, the influence of alkali (NaOH) treatment on the mechanical, thermal and morphological properties of eco-composites
of short flax fiber/poly(lactic acid) (PLA) was investigated. SEM analysis conducted on alkali treated flax fibers showed
that the packed structure of the fibrils was deformed by the removal non-cellulosic materials. The fibrils were separated
from each other and the surface roughness of the alkali treated flax fibers was improved. The mechanical tests indicated that
the modulus of the untreated fiber/PLA composites was higher than that of PLA; on the other hand the modulus of alkali treated
flax fiber/PLA was lower than PLA. Thermal properties of the PLA in the treated flax fiber composites were also affected.
Tg values of treated flax fiber composites were lowered by nearly 10 °C for 10% NaOH treatment and 15 °C for 30% NaOH treatment.
A bimodal melting behavior was observed for treated fiber composites different than both of neat PLA and untreated fiber composites.
Furthermore, wide angle X-ray diffraction analysis showed that the crystalline structure of cellulose of flax fibers changed
from cellulose-I structure to cellulose-II. 相似文献