共查询到20条相似文献，搜索用时 62 毫秒
1.
Plasticization and toughness of polylactide (PLA) are of interesting due to its poor machinability and brittleness. Here, low and high macromolecular weight of Poly(diethylene glycol adipate)s (L-PDEGA and H-PDEGA) were used to plasticize and toughen PLA simultaneously. The results showed that the mechanical properties of PLA remained almost unchanged when only 5 wt% L-PDEGA was added. However, H-PDEGA were effective in lowering the glass transition temperatures as well as in increasing the elongation at break and the impact strength. Compared with neat PLA, the crystallinity of PLA increased with increasing H-PDEGA content. When 20 wt% H-PDEGA was added, the impact strength and the elongation at break increased from 3.1 kJ/m2 and 5.6 % of neat PLA to 68.3 kJ/m2 to 272.4 %, respectively. Additionally, morphological study revealed that the fracture behavior of PLA had been changed from brittle to ductile after H-PDEGA incorporated. The results of rheological analysis showed that the storage modulus and complex viscosity in the melt state of the blends were decreased compared with that of neat PLA. 相似文献
2.
In this study, PLA/PC blends were prepared in order to investigate the effects of the addition of PC loading level into PLA matrix on the mechanical properties of these blends. After that, PLA/PC (70/30), which has the lowest tensile strength value, was selected as a control sample for the compatibilization study. Commercial styrene-acrylic multi-functional-epoxide oligomeric agent (SAmfE), styrene maleic anhydride copolymer (SMA), tetrasilanol phenyl polyhedral oligomeric silsesquioxane (T-POSS) and glycidyl isooctyl-polyhedral oligomeric silsesquioxane (G-POSS) were used as compatibilizers for PLA/PC blends. The variation of mechanical, thermal, structural and morphological properties were examined by conducting tensile tests, dynamic mechanical analyses, differential scanning calorimetry, Fourier Transform IR and scanning electron microscope analyses. Tensile test results showed that the tensile strength and elongation at break values of the PLA/PC blend compatibilized with SAmfE were higher than those of the other blends. DSC analyses revealed that Tg and Tm values of the blends were not significantly affected by compatibilizer but, degree of crystallinity was found to be sensitive to compatibilizer type. DMA results showed that the best mechanical properties were obtained for the PLA/PC/SAmfE blend. When all of the results evaluated, it was found that the SAmfE is the most effective compatibilizer among the using compatibilizer types for PLA/PC blends. 相似文献
3.
This article describes the effect of compatibilising agent on natural rubber (NR)/chitosan (CS) blends. Maleic anhydride (MA)
was used as the compatibiliser. The mechanical properties such as tensile strength, elongation at break, and modulus at various
elongations of compatibilised NR/CS blends were studied by universal testing machine and the surface hardness was studied
by Shore A Durometer. The interaction between the two components was analyzed by calculating the fraction of bound rubber
in the blend from the relative weight loss data in benzene as the solvent. The incorporation of MA into NR/CS blends improved
tensile strength up to 15 % of chitosan in the blend and above which it decreased. The elongations at break of the MA treated
blends decreased and a drastic enhancement of surface hardness was observed by the addition of MA in the blend. The interfacial
reactivity (adhesion) of NR/CS blends was studied as a function of the incorporation of compatibiliser by the estimation of
relative weight loss. The data revealed an increase in the interfacial adhesion between NR and CS, resulting in an improvement
of the gel fraction (%) in the blend. The effect of thermal ageing on the mechanical properties of the compatibilised blends
was also studied. The morphology of the compatibilised blends was studied by scanning electron microscopy and it shows a continuous
morphology. 相似文献
4.
Biodegradable materials are considered as alternative to synthetic materials to alleviate the environmental burdens caused by petroleum based synthetic materials. Biopolymer blends have been extensively researched to improve the material properties of biopolymer-based materials for potential replacement of non-biodegradable materials. Compatible blends of pre-gelatinized maize starch (uncomplexed or complexed with stearic acid) and commercial zein in 0.1 M NaOH were used to produce the films. The effect of the ratio of uncomplexed starch, zein and starch complexed with stearic acid on the tensile, water vapour and oxygen barrier and thermal properties of the composite films were investigated. Blending zein with starch increased the tensile strength and reduced the tensile strain compared to starch films. Addition of starch complexed with stearic acid to the blend further increased the tensile strength and decreased the elongation at break. Both blending zein with starch and addition of starch complexed with stearic acid to the blend decreased the water vapour permeability, however, the oxygen permeability was increased compared to starch films. The starch-zein blend films had an endothermic temperature and thermal transition in between the uncomplexed maize starch and zein films suggesting possible compatibility at molecular level. The microstructure of the blend films also showed good miscibility of pre-gelatinized starch and commercial zein. In conclusion alkaline solvent (0.1 M NaOH) could produce compatible starch-zein blends that can produce films with improved tensile strength and water vapour permeability compared to starch films. 相似文献
5.
Shuiping Li Qing Lin Huajun Zhu Chong Cui Haijun Hou Tingting Lv Yanbo Li 《Fibers and Polymers》2016,17(2):282-288
Glass fiber, GF, which was first hydroxylated and silanized, was incorporated into epoxy resin modified with amino-terminated hyperbranched polymer (ATHBP) to obtain high performance composite. The effects of GFs content on the mechanical properties of composites were investigated, discussing the results from flexural, tensile, and impact tests. The composites revealed noticeable improvement in flexural strength, tensile strength as well as impact strength but slow decrease in elongation at break, compared to the epoxy/ATHBP thermoset. FESEM morphology results indicated the good compatibility between epoxy matrix and GF in the appearance of ATHBP and showed that the toughening mechanism was mainly attributed to the stress transfer mechanism. 相似文献
6.
PLA/LPCL/HPCL blends composed of poly(lactic acid) (PLA), low molecular weight poly(ε-caprolactone) (LPCL), and high molecular weight poly(ε-caprolactone) (HPCL) were prepared by melt blending for bioabsorbable filament sutures. The effects of blend composition
and blending time on the ester interchange reaction by alcoholysis in the PLA/LPCL/HPCL blends were studied. Their thermal
properties and the miscibility due to the ester interchange reaction were investigated by1H-NMR, DSC, X-ray, and UTM analyses. The hydroxyl group contents of LPCL in the blends decreased by the ester interchange
reaction due to alcoholysis. Thus, the copolymer was formed by the ester interchange reaction at 220 °C for 30–60 minutes.
The thermal properties of PLA/LPCL/HPCL blends such as melting temperature and heat of fusion decreased with increasing ester
interchange reaction levels. However, the miscibility among the three polymers was improved greatly by ester interchange reaction.
Tensile strength and modulus of PLA/LPCL/HPCL blend fibers increased with increasing HPCL content, while the elongation at
break of the blend fibers increased with increasing LPCL content. 相似文献
7.
In this study, in-situ polypropylene/polystyrene (PP/PS) blends were prepared via a reactive extrusion technique. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the generation of polypropylene-grafted-polystyrene (PP-g-PS) copolymer in the reactive process. The morphology of the in-situ PP/PS blend tended to form a homogeneous structure, as observed by scanning electron microscopy (SEM). Owing to the introduction of PP-g-PS in the reactive extrusion, a remarkable enhancement of mechanical properties was achieved for the in-situ PP/PS blend. The elongation at break of the in-situ PP/PS blend with 15 wt% PS can reach 500 %, over 10 times higher than that of the normal PP/PS blend. Differential scanning calorimetry (DSC) showed an increased crystallization temperature of PP, which can be attributed to the heterogeneous nucleation effect of the PS and grafted PS. The analysis of wide angle X-ray diffraction (WAXD) indicated the development of beta crystals in the in-situ PP/PS blend. 相似文献
8.
Mechanical properties of biodegradable poly(butylene succinate-co-terephthalate) (PBST) fibers with 70 mol% butylene terephthalate (BT) were intensively investigated. Chemical structure composed of hard BT units and soft butylene succinate (BS) units made contributions to the higher elongation at break and lower initial modulus of PBST fibers than poly(butylene terephthalate) (PBT) fibers. Moreover, PBST fibers had better elastic properties than PBT fibers by exploring their elastic recovery. The stretch elastic recovery mechanism of PBST fibers was clarified from the point of crystal structure transition. According to the preliminary studies by wide angle X-ray diffraction (WAXD) measurements, two polymorphs (α form and β form) were confirmed when PBST fibers were applied to different deformations. With the help of intensive study by small angle X-ray scattering (SAXS) measurements, the crystal structure transition of PBST fibers was further verified. 相似文献
9.
The thermal behavior, morphology, ester-interchange reaction of Poly(trimethylene terephthalate) (PTT)/Poly(ethylene terephthalate)
(PET) melt blends were investigated over the whole composition range(xPTT/(1-x)PET) using a twinscrew Brabender. The melt
blends were analyzed by differential scanning calorimetry (DSC), nuclear magnetic resonance spectroscopy (13C-NMR), and scanning electron microscopy (SEM). Single glass transition temperature (T
g
) and cold crystallization temperature (T
cc
) were observed in all melt blends. Melt blends were found to be due to the ester-interchange reaction in PTT/PET blend. Also
the randomness of copolymer increases because transesterification between PTT and PET increases with increasing blending time.
This reaction increases homogeneity of the blends and decreases the degree of crystallinity of the melt blends. In PTT-rich
blends, mechanical properties decrease with increase of PET content compared with that of pure PTT. And, in PET-rich blends,
tensile modulus decreases with increase of PTT content, but tensile strength and elongation is similar to that of pure PET. 相似文献
10.
This research evaluates the miscibility and performance of polypropylene (PP)/polybutylene succinate (PBS) and PP/polylactic acid (PLA) blend and natural-flour-filled, PP/PLA and PP/PBS blend bio-composites. The melting temperature (T m ) and glass transition temperature (T g ) of pure PP, PBS and PLA showed a single peak but differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) presented two peaks for the T m and T g of the PP/PBS and PP/PLA blends. These results indicated that the PP/PBS and PP/PLA blend systems existed as immiscible blends. These results were also confirmed by the scanning electron microscopy (SEM) micrographs of the tensile fracture surface of the PP/PBS and PP/ PLA blends. At a PP/PBS and PP/PLA blend ratio of 70/30, the tensile and flexural strengths of bamboo flour (BF)- and wood flour (WF)-filled, PP/PBS and PP/PLA blend bio-composites were similar to those of BF- and WF-filled, PP and PBS bio-composites. In addition, these strengths of maleic anhydride-grafted PP (MAPP)- and acrylic acid-grafted PP (AAPP)-treated, BF- and WF-filled, PP/PBS and PP/PLA blend bio-composites were higher than those of non-treated bio-composites. 相似文献
11.
David J. Sessa Kristen K. WoodsAbdellatif A. Mohamed Debra E. Palmquist 《Industrial Crops and Products》2011,33(1):57-62
Melt-processed blends of zein and polyvinylpyrrolidone (PVP) of varying molecular weights (55K, 360K and 1.3M) were compared based on mechanical and thermal properties. Generally, all samples stored at 50% RH exhibited a slight improvement in tensile strength, with the PVP360K samples showing the greatest improvement. At the higher levels of PVP, samples stored at 70% RH showed a decrease in tensile strength. Elongation was also more significantly impacted at higher humidity, with the higher levels of PVP causing greater elongation increases. Differential scanning calorimetry data for the blends showed single Tg values intermediate between the zein and PVP controls. Kinetic thermogravimetric data suggested a multi-step degradation interaction for the zein/PVP blends. Scanning electron microscope imaging of compression molded samples showed homogeneous surface contours for even the 20% PVP1.3M blend. Melt-processed blends of zein with polyvinylpyrrolidone of various molecular weights appear to be compatible. This work represents the first melt-processed blend of zein with PVP to generate a compatible blend. 相似文献
12.
Mohammad Ali Tavanaie Ahmad Mousavi Shoushtari Fatemeh Goharpey Mohammad Reza Mojtahedi 《Fibers and Polymers》2013,14(3):396-404
Different shapes of dispersed phase such as sphere, laminar and fibrillar can form in the matrix phase of polymer blends. Production of blend fibers in melt spinning process can result more effective in fibrillar phase morphology formation than in other processes. In this research, the matrix-fibril morphology development during the melt spinning of polypropylene/poly(butylenes terephthalate) was studied. The shapes of blend dispersed phase collected from different zones of the melt spinning line were evaluated by scanning electron micrographs (SEM) and rheological mechanical spectra (RMS). The results showed that fibrillar shape could not be created in the PP/PBT blend fiber samples exited from the spinneret orifice (gravity spun fibers) at low contents (5 percent) of the PBT dispersed phase. However, a complete fibrillar structure was formed in all the as-spun PP/PBT blend fiber samples (melt drawn). The rheological evaluations confirmed a network structure resulting from fibril formation for the samples with high contents (20–40 %) of the PBT dispersed phase and the formation of spherical shape with low contents (5–10 %) of the PBT dispersed phase in matrix of the blend fibers. It was observed that the flow fields of processing zones and blend ratio, in producing the blend fibers, have intensive effects on morphological variations; besides there was a strong relation between the mechanical and morphological properties. 相似文献
13.
The aim of this paper is to study the effect of fibre content on mechanical and morphological properties and thermal stability of roselle fibres (RFs) reinforced polyurethane (TPU) composites. The RF/TPU composites were prepared at difference fibre contents; 10, 20, 30, 40 and 50 wt% by melt mixed mixer and hot press at 170 °C. Mechanical (tensile, flexural and impact strength) and Thermogravimetric analysis (TGA) properties of RF/TPU composites were measured according to ASTM standard. Obtained results indicated that effect of fibre contents display improved tensile and flexural and impact strength properties. RF/TPU composites show the best mechanical and thermal properties at 40 wt% roselle fibre content. Scanning electron microscopy (SEM) micrograph of fractured tensile sample of the roselle composite revealed good fibre/matrix bonding. TGA showed that RF/TPU with difference fibre contents had improved thermal stability. 相似文献
14.
Hye Jin Zo Seong Hwan Joo Tak Kim Pan Seok Seo Jin Hong Kim Jong S. Park 《Fibers and Polymers》2014,15(5):1071-1077
In this article, we demonstrated the preparation of carbon-fiber-reinforced composites using a polyamide 6 (PA6)/thermoplastic polyurethane (TPU) blend, in which the addition of TPU resulted in superior mechanical performances and increased thermal stability. According to various characterization techniques, these results are attributed to an enhanced adhesion and a homogeneous dispersion of long-carbon-fibers (LCFs) with TPU sizing in blended polymer matrix. Above all, dynamic-mechanical thermal analysis (DMTA) measurements clearly show that the dynamic storage modulus (E') of the blend composites is increased by threefold with temperature ranges below and above the glass transition temperature. The presence of LCFs in TPU systems induces effective fiber orientation, exhibiting simultaneous improvements in the tensile strength, flexural strength, and thermal stability. 相似文献
15.
Based on the situ preparation of silica nanoparticles (SiO2) on the surface of Graphene nanoplatelets (GNPs) in the previous work, these unique three dimensional (3D) materials were introduced into epoxy resin to study the reinforcing and toughening synergy effect on the composites. Firstly, the tensile tests showed that Graphene/SiO2 hybrid materials attached with different size of SiO2 particles exhibited different reinforcing and toughening effect on the composites. With the increasing of the diameter of SiO2 particles, the toughness and strength properties of the composites firstly improved and then decreased, and when the average diameter was 0.14 μm, the elongation reached the max.. Meanwhile, the fractured surfaces presented on SEM images were consistent with the results of the tensile tests, which further explained the hybrid materials increased the interfacial adhesion between the fillers and matrix, leading to significant improvement in mechanical properties. Moreover, the DSC curves demonstrated that Graphene/SiO2 hybrid materials accelerated the curing process of epoxy resin due to the cross-link structure between fillers and matrix. Lastly, the crack propagation modes were built to clarify the synergy effect mechanism of reinforcing and toughening on nanoparticles/epoxy resin composites. 相似文献
16.
Eliangela de M. TeixeiraAntônio A.S. Curvelo Ana C. CorrêaJosé M. Marconcini Gregory M. GlennLuiz H.C. Mattoso 《Industrial Crops and Products》2012,37(1):61-68
Cassava bagasse is an inexpensive and broadly available waste byproduct from cassava starch production. It contains roughly 50% cassava starch along with mostly fiber and could be a valuable feedstock for various bioproducts. Cassava bagasse and cassava starch were used in this study to make fiber-reinforced thermoplastic starch (TPSB and TPSI, respectively). In addition, blends of poly (lactic acid) and TPSI (20%) and TPSB (5, 10, 15, 20%) were prepared as a means of producing low cost composite materials with good performance. The TPS and PLA blends were prepared by extrusion and their morphological, mechanical, spectral, and thermal properties were evaluated. The results showed the feasibility of obtaining thermoplastic starches from cassava bagasse. The presence of fiber in the bagasse acted as reinforcement in the TPS matrix and increased the maximum tensile strength (0.60 MPa) and the tensile modulus (41.6 MPa) compared to cassava starch TPS (0.40 and 2.04 MPa, respectively). As expected, blending TPS with PLA reduced the tensile strength (55.4 MPa) and modulus (2.4 GPa) of neat PLA. At higher TPSB content (20%) the maximum strength (19.9 MPa) and tensile modulus (1.7 GPa) were reduced about 64% and 32%, respectively, compared to the PLA matrix. In comparison, the tensile strength (16.7) and modulus (1.2 GPa) of PLA blends made with TPSI were reduced 70% and 51% respectively. The fiber from the cassava bagasse was considered a filler since no increase in tensile strength of PLA/TPS blends was observed. The TPSI (33.1%) had higher elongation to break compared to both TPSB (4.9%) and PLA (2.6%). The elongation to break increased from 2.6% to 14.5% by blending TPSI with PLA. In contrast, elongation to break decreased slightly by blending TPSB with PLA. Thermal analysis indicated there was some low level of interaction between PLA and TPS. In PLA/TPSB blends, the TPSB increased the crystallinity of the PLA component compared to neat PLA. The fiber component of TPSB appeared to have a nucleating effect favoring PLA crystallization. 相似文献
17.
Xiangyu Yan Yan Zhao Yanping Hao Hongwei Pan Huiliang Zhang Zhe Wang Lisong Dong 《Fibers and Polymers》2017,18(11):2049-2059
Poly(L-lactide) (PLLA)/poly(D-lactide) (PDLA)/poly(ethylene octene) grafted with glycidyl methacrylate (GPOE) were prepared by simple melt blending method at PDLA loadings from 1 to 5 wt%. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) demonstrated the formation of the stereocomplex in the blends. The addition of PDLA led to the increase of nucleation density from polarized microscope (POM) observations. Rheological measurements indicated that the blends exhibited a rheological fluid-solid transition and an enhanced elastic behavior in that ternary system as the PDLA loadings reached up to 5 wt%. By adding 1-2 wt% PDLA, the ternary system has better tensile and impact properties. Dynamic Mechanical Analysis (DMA) results showed that SC crystal formation and its effect on the enhancement of thermal stability at higher temperature. It is interesting that the enzymatic degradation rates have been enhanced clearly in the PLLA/PDLA/GPOE blends than in the PLLA/GPOE blend, which may be of great use and significance for the wider practical application of PLLA/GPOE blends. 相似文献
18.
Poly(trimethylene terephthalate) (PTT)/poly(ethylene naphthalate) (PEN) blends of various compositions were prepared by the
solution-blending and melt-blending methods. The changes in miscibility and crystallization behaviors of the blends upon thermal
treatment above the melting temperature of the blends at 280°C were investigated by using DSC, DMA,1H NMR, and SAXS analyses. Without any thermal treatment, the blend systems were not miscible, and the thermal transitions,
such as glass transition, cold crystallization, and crystal melting of the individual components were observed in the DSC
and DMA analyses. With thermal treatment, though, they became miscible as the thermal transitions of each component disappeared
and single glass transition peaks were observed in the thermal analysis. The chain randomness determined using1H NMR spectroscopy revealed that thermal treatment at 280°C for more than 30 min brought about transesterification reactions
between the PTT and PEN segments resulting in an increase in their miscibility. These results were confirmed by the small
angle X-ray analysis conducted to determine the long period (L), the thickness of the crystalline lamella stack (l
c
), and the thickness of the amorphous region (l
a
). After short thermal treatment, the melt-blended sample followed the values for the individual components. However, with
extended thermal treatment, the blend became homogeneous, possessing different crystalline morphologies which resulted in
different values ofL, l
c
, andl
a
. 相似文献
19.
The HVI properties and Mantis® single fiber tensile properties were analyzed to evaluate the relationship between fiber and bundle tensile properties. For this study, a new method has been developed for estimating the modulus and toughness of cotton fiber bundles directly from the HVI tenacity-elongation curves. The single fiber tensile properties were shown to be translated well into the bundle tensile properties. The single fiber breaking elongation was found to be the most significant contributing factor to bundle tensile properties. The bundle breaking elongation and toughness were shown to increase as the single fiber breaking elongation increased. The bundle modulus increased as the single fiber breaking elongation and/or standard deviation of single fiber breaking elongation decreased. 相似文献
20.
S. Jayabal S. Velumani P. Navaneethakrishnan K. Palanikumar 《Fibers and Polymers》2013,14(9):1505-1514
The research on coir-polyester composites initiated the interest in the development of woven coir fiber-reinforced polyester composites. The mechanical properties of woven coir-polyester composites were evaluated as per ASTM standards and the machinability behavior was studied by conducting drilling tests in this investigation. The woven coir-polyester composites exhibited the average values of tensile, flexural and impact strength of 19.9 MPa, 31.3 MPa and 49.9 kJ/m2 respectively. The effect of NaOH treatment on the improvement of mechanical properties of woven coir-polyester composites were studied in this investigation. The 40 % increase of tensile strength, 42 % increase of flexural strength and 20 % increase of impact strength were achieved by treated woven coir fiber-reinforced polyester composites. The regression models for predicting thrust force, torque and tool wear in drilling of woven coir-polyester composites were developed and the effect of drilling parameters were analyzed. 相似文献