共查询到20条相似文献,搜索用时 31 毫秒
1.
Radka Balkova Sona Hermanova Stanislava Voberkova Pavel Damborsky Lukas Richtera Jirina Omelkova Josef Jancar 《Journal of Polymers and the Environment》2014,22(2):190-199
Biodegradation of poly(ε-caprolactone) composite with graphite oxide (GO) by the action of Bacillus subtilis (BS) was studied in this work. Nanocomposite produced in a form of thin film was exposed to nutrient cultivation medium with BS as well as to abiotic nutrient medium (control run) at 30 °C. The matrix itself was exposed to the same conditions for comparison. Biodegradation was demonstrated by the weight loss and the decrease of molecular weight during 21 days of the experiment as well as by changes in the surface morphology and structure. Both degraded and control materials were characterized by confocal laser scanning microscopy, differential scanning calorimetry, thermogravimetry, and Fourier transform infrared spectroscopy with attenuated total reflectance. The bacterial growth expressed as the measure of the optical density/turbidity in McFarland units and pH of medium were measured in situ during the experiment. Lipolytic activity of BS was determined by spectrophotometric assay. Degradation process was accompanied by the increase of matrix crystallinity degree. GO served as nucleating agent and facilitated absorption of cultivation media into the composite which led to the increase of the crystallinity degree also for control nanocomposite specimens. It was not evaluated to be promoter of biodegradation. The surface cracks formation was initiated by BS action. Large surface cracks were formed on BS-degraded composite surfaces while surface erosion was more significant on BS-degraded matrix. 相似文献
2.
Peng Chen Kesong Yu Yaqiao Wang Wenbo Wang Hongfu Zhou Hangquan Li Jianguo Mi Xiangdong Wang 《Journal of Polymers and the Environment》2018,26(9):3718-3730
Composite nucleating agent (CNA) consisting of zinc oxide as a crystallization promoter and phenylphosphonic acid zinc salt (PPZn) as an heterogeneous nucleation agent was employed to improve the crystallization behaviors of branched poly (lactic acid) (B-PLA) which was prepared by use of multi-functional epoxy-based chain extender (CE). The differential scanning calorimeter results showed that the crystallinity and crystallization temperature of prepared B-PLA/CNA were higher than that of linear poly (lactic acid) (L-PLA) and B-PLA at a high cooling rate. The corresponding phenomena of heterogeneous nucleation of B-PLA/CNA were observed by means of polarized optical microscope. The crystalline mechanism research results show that the degradation reaction and chain extending reaction were occurred simultaneously after the addition of CE and CNA into the PLA, PPZn as an effective nucleation points could increase the nucleation density and the degraded short molecular chains with higher chain mobility would improve crystal growth during the crystallization of the branched PLA. Non-isothermal cold crystallization kinetics of various B-PLA with different content of CNA was studied. The corresponding result showed that the crystallinity and crystallization rate increased obviously with the CNA content greater than or equal to 5phr, as well as the crystallization time decreased. The similar experimental results of non-isothermal and isothermal melt crystallization kinetics also showed that CNA had a significant impact on crystallization behavior of B-PLA. 相似文献
3.
Effect of Nucleating Agents on Physical Properties of Poly(lactic acid) and Its Blend with Natural Rubber 总被引:1,自引:0,他引:1
Poly(lactic acid) (PLA) presents high strength and modulus, but very low toughness as well as slow crystallization. Natural
rubber (NR) was blended to enhance the toughness and nucleating agent was added to improve the crystallization. Cyclodextrin
(CD), considered as a green compound, as well as calcium carbonate (CaCO3) and talc were used as nucleating agents. Effects of these nucleating agents on crystallization, mechanical properties and
morphology of neat PLA and PLA/NR blend were investigated. It was found that the addition of talc and CD decreased cold crystallization
temperature (Tcc) of the PLA. Same result was obtained in PLA/NR blend containing talc. All nucleating agents increased the degree of crystallinity
(ΧC) of PLA, whereas only talc and CaCO3 increased ΧC of PLA in PLA/NR blends. The enhanced toughness of PLA by the addition of nucleating agent was attributed to its increased
crystallinity, as well as decreased spherulite size. For PLA/NR blends, the increase in toughness was mainly contributed by
the presence of the rubber. 相似文献
4.
Margaret J. Sobkowicz John R. Dorgan Keith W. Gneshin Andrew M. Herring J. Thomas McKinnon 《Journal of Polymers and the Environment》2008,16(2):131-140
Nucleation of polylactide and polypropylene using novel renewable resource biobased carbon nanospheres (CNS) is investigated
using differential scanning calorimetry and polarized optical microscopy. Isothermal studies near the optimal crystallization
temperature demonstrate at least a five-fold increase in crystallization rate in PP but only a 1.4 times faster crystallization
in PLA. Non-isothermal studies reveal an asymptotic relationship of the maximum crystallization temperature with increasing
CNS weight loading in PP and no relationship in PLA. Microscopy indicates some aggregation in the solution blended samples
and that average spherulite size is reduced 10-fold due to faster nucleation in the composites as compared to the neat polymer.
The fractional crystallinity achieved during non-isothermal crystallization increases by about 7% with addition of a small
amount of CNS and decreases with weight loading higher than 1%. The crystallization rates obtained in polypropylene are competitive
with widely used mineral talc nucleating agents. 相似文献
5.
This study is concerned with the behavior of samples based on nylon 6/zinc (Ny6/Zn) composite material in high salinity water that contains NaCl (3.5 wt%) and in aqueous solution of HCl (0.5 N and 1 N). The samples were obtained from parts prepared by in situ anionic ring-opening polymerization of ?-caprolactam (CL) in the presence of zinc (Zn), as filler (15 wt%) using the rotational molding technique. This type of composite was evaluated by the testing of swelling degree, structural modifications, evolution of hydrogen and electrochemical behavior. The properties of Ny6/Zn composite material have ascertained through the combined use of more analysis methods: attenuated total reflectance Fourier transform infrared spectroscopy, wide-angle X-ray diffraction technique, scanning electron microscopy, swelling and electrochemical measurements. It was revealed that regarding swelling behavior the Ny6 matrix has an important role while Zn filler contributes especially to the (electro)chemical corrosion. 相似文献
6.
Christopher Thellen Megan Coyne Danielle Froio Margaret Auerbach Carl Wirsen Jo Ann Ratto 《Journal of Polymers and the Environment》2008,16(1):1-11
A series of polyhydroxyalkanoates (PHA), all containing 1% nucleating agent but varying in structure, were melt-processed
into films through single screw extrusion techniques. This series consisted of three polyhydroxybutyrate (PHB) and three polyhydroxybutyrate-valerate
(PHBV) resins with varying valerate content. Processing parameters of temperature in the barrel (165–173 °C) and chill rolls
(60 °C) were optimized to obtain cast films. The gel-permeation chromatography (GPC) results showed a loss of 8–19% of the
polymer’s initial molecular weight due to extrusion processing. Modulated differential scanning calorimetry (MDSC) displayed
glass transition temperatures of the films ranging from −4.6 to 6.7 °C depending on the amount of crystallinity in the film.
DSC data were also used to calculate the percent crystallinity of each sample and slightly higher crystallinity was observed
in the PHBV series of samples. X-ray diffraction patterns did not vary significantly for any of the samples and crystallinity
was confirmed with X-ray data. Dynamic mechanical analysis (DMA) verified the glass transition trends for the films from DSC
while loss modulus (E′) reported at 20 °C showed that the PHBV (3,950–3,600 MPa) had the higher E′ values than the PHB (3,500–2,698 MPa) samples. The Young’s modulus values of the PHB and PHBV samples ranged from 700 to
900 MPa and 900 to 1,500 MPa, respectively. Polarized light microscopy images revealed gel particles in the films processed
through single-screw extrusion, which may have caused diminished Young’s modulus and tensile strength of these films. The
PHBV film samples exhibited the greatest barrier properties to oxygen and water vapor when compared to the PHB film samples.
The average oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) for the PHBV samples was 247 (cc-mil/m2-day) and 118 (g-mil/m2-day), respectively; while the average OTR and WVTR for the PHB samples was 350 (cc-mil/m2-day) and 178 (g-mil/m2-day), respectively. Biodegradation data of the films in the marine environment demonstrated that all PHA film samples achieved
a minimum of 70% mineralization in 40 days when run in accordance with ASTM 6691. For static and dynamic incubation experiments
in seawater, microbial action resulting in weight loss as a function of time showed all samples to be highly biodegradable
and correlated with the ASTM 6691 biodegradation data. 相似文献
7.
Shikha Jain Manjusri Misra Amar K. Mohanty Anup K. Ghosh 《Journal of Polymers and the Environment》2012,20(4):1027-1037
In the present study, influence of talc on thermal, mechanical and rheological behavior of PLA is investigated and the structure?Cproperty correlation for the PLA/talc composites is established. Poly(lactic acid)/talc composites are prepared by melt mixing of PLA with talc in twin screw extruder followed by blown film processing. Various characterizations techniques are used to evaluate thermal, morphological, mechanical and rheological behavior of PLA/talc composites and its blown film. DSC analysis showed that degree of crystallinity of PLA/talc composites was higher than that of neat PLA because of nucleating ability of talc. Spherulite morphology of PLA/talc composites showed that talc has increased nucleation density of spherulite having smaller radius than that of neat PLA. Talc is effective in enhancing tensile modulus and storage modulus of PLA due to reinforcing ability of talc particles. 相似文献
8.
Larissa Stieven Montagna Thaís Larissa do Amaral Montanheiro Fábio Roberto Passador Ana Paula Lemes Mirabel Cerqueira Rezende 《Journal of Polymers and the Environment》2018,26(4):1511-1519
The potential use of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/graphite nanosheets (GNS) as a biodegradable nanocomposite has been explored. PHBV/GNS nanocomposites films were prepared by solution casting at various concentrations of GNS—0.25, 0.50 and 1.00 wt% GNS. The films were exposed to artificial ultraviolet radiation (UV) during 52 h. The effect of GNS on PHBV photodegradation was investigated and compared to neat PHBV film. The artificial photodegradation induced changes in physical (weight loss), chemical carbonyl index by Fourier transform infrared spectroscopy, thermal degree of crystallinity and melting temperature by differential scanning calorimetry and morphological scanning electron microscopy characteristics. Based on the results obtained from aforementioned analyzes it was verified that GNS inhibits the oxidative degradation of PHBV matrix. 相似文献
9.
A. P. Lemes M. A. Soto-Oviedo W. R. Waldman L. H. Innocentini-Mei N. Durán 《Journal of Polymers and the Environment》2010,18(3):250-259
The effect of lignosulfonate on poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, was studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and
thermogravimetric analysis (TGA). The PHBV/lignosulfonate samples were prepared by melt mixing in an internal mixer. SEM showed
that PHBV/lignosulfonate samples present a cracked surface that is more intense in mixtures with high lignosulfonate proportions.
According to DSC, melting and glass transition temperatures of the PHBV matrix decrease with lignosulfonate addition. The
same effect was observed for melting enthalpies (ΔHm), which indicates a decrease of crystallinity. TGA showed that thermal stability of PHBV/lignosulfonate samples was shifted
to lower temperatures, which indicates the existence of an interaction between the thermal decomposition processes of PHBV
and lignosulfonate. 相似文献
10.
Yue Zhang Hongsheng Zhang Luping Ni Qilin Zhou Weihong Guo Chifei Wu 《Journal of Polymers and the Environment》2010,18(4):647-653
Recycled poly(ethylene terephthalate) (R-PET) was blended with 15–30 wt% of styrene–ethylene/butylenes–styrene (SEBS) block
copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Effects of nucleation and toughening of the elastomers were evaluated
systematically by study of morphology, crystallization, thermal and mechanical properties of the blend. The addition of 30 wt%
SEBS promoted the formation of co-continuous structure of the blend and caused the fracture mechanism to change from strain
softening to strain hardening. Addition of SEBS-g-MA resulted in significant modification of phase morphology and obviously
improved the impact strength. The compatibilization reaction of PET with SEBS-g-MA accelerated the crystallization of PET
and increased the crystallinity. The shifts in glass transition temperature of PET towards that of SEBS-g-MA and the higher
modulus for R-PET/SEBS-g-MA (70/30) blend found by DMA are also indications of better interactions under the conditions of
compatibilization and interpenetrating structure. 相似文献
11.
Serap Cesur 《Journal of Polymers and the Environment》2018,26(4):1425-1444
Because environmental pollution caused by plastic waste is a major problem investigations concerning biodegradable packaging are important and required. In this study, the biodegradation of PCL composite films with organic (glycerol monooleate and oleic acid) and inorganic additives (organo nano clay) was investigated to understand which additive and the amount of additive was more effective for biodegradation. The relationship between the degree of crystallinity and the effect of additives on the biodegradability of polycaprolactone (PCL) was examined. PCL composite films were prepared using organo nano clay (0.1–0.4–1–3 wt%) and oleic acid (1–3–5 wt%) or GMO (1–3–5 wt%). The 35 films prepared with PCL (P), clay (C), oleic acid (O), or glycerol monooleate (G) are coded as P_C#wt%_O (or G)#wt%. The composite films, P_C0.4_O5 contains 0.4 wt% clay and 5 wt% oleic acid and the P_C3_G1 contains 3 wt% clay and 1 wt% glycerol monooleate. The biodegradation of PCL films in simulated soil was studied for 36 months. The films were periodically removed from the simulated soil and film thicknesses, weight losses, visual changes, crystal structures, and a functional group analyses were performed. PCL composite films are separated into three groups, depending on degradation time, (1) films that degraded before 8 months (fast degradation), (2) films that degraded around 24 months (similar to neat PCL), and (3) films that take longer to degrade (slow degradation). The films in the first group are PCL films with 1 and 3 wt% clay additive and they begin to biodegrade at the 5th month. However, a composite film of PCL with only 0.4 wt% clay and 5 wt% GMO addition has the shortest degradation time and degraded in 5 months. The films in the last group are; P_G3, P_G5, P_C0.1, P_C0.1_O1, and P_C0.1_O5 and they took around 30 months for biodegradation. It was observed that increasing the organo nanoclay additive increases the biodegradability by disrupting the crystal structure and causing a defective crystal formation. The addition of GMO with organo nano clay also accelerates biodegradation. The addition of organo nano clay in an amount as small as 0.1 wt% acts as the nucleating agent, increases the degree of crystallinity of the PCL composites, and slows the biodegradation period by increasing the time. 相似文献
12.
Biodegradation Study of Starch-graft-Acrylonitrile Copolymer 总被引:1,自引:0,他引:1
Amir H. Navarchian Amir Sharafi Roha K. Kermanshahi 《Journal of Polymers and the Environment》2013,21(1):233-244
In this study the biodegradability of starch-graft-acrylonitrile (St-g-AN) copolymer has been investigated using some microorganisms including Aspergillus niger. The fungus A. niger was isolated from the soil and from the wastewater of an acrylic fiber company. The effects of four factors including environment temperature, primary inoculum concentration, pH and weight of copolymer film, on the biomass generation as a measure of biodegradation rate of copolymer, were studied using Taguchi experimental design. The statistical analysis of the results showed that the primary inoculum concentration and temperature were the most important factors affecting the biodegradation of St-g-AN copolymer. The optimum levels of temperature, pH, inoculum concentration, and weight of films to attain the maximum biodegradation (as much as 8.59 % by weight percentage during 28 days) were obtained as 30 °C, 4.75, 108 spore/mL, and 1.1 g, respectively. The changes in the structure and morphological properties of the copolymer before and after degradation were determined using transform infrared spectroscopy and scanning electron microscopy. 相似文献
13.
Anna Zubrowska Ewa Piorkowska Joanna Bojda 《Journal of Polymers and the Environment》2018,26(1):145-151
Blending of polylactide (PLA) with low stereoregularity and polyhedral oligomeric silsesquioxane grafted with arms of poly(ethylene glycol) methyl ether, acting as a plasticizer, allowed us previously to obtain a novel stable elastomeric-like material. The present contribution focuses on the properties of semi-crystalline PLA plasticized with this compound. Melt blends of PLA with 5–15 wt% of the plasticizer, were compression molded, quenched and annealed, which enabled cold-crystallization. The glass transition temperature of the blends and their drawability depended on their crystallinity and plasticizer content. The best ductility was reached at the plasticizer content of 15 wt%; the achieved strain at break was 6.5 (650%) and 1.3 (130%), for the quenched and annealed material, respectively. The latter value exceeded 20 times the strain at break of neat crystalline PLA. The tensile toughness of the annealed 15 wt% blend was 12 times larger than that of crystalline PLA. Moreover, annealing of 15 wt% blend improved its yield strength by 40%. Despite the two peaks of the loss modulus, indicating the two glass transitions in this blend, no heterogeneities were found by scanning electron microscopy, indicating that the plasticizer enriched phase formed instead of distinct inclusions of the plasticizer. 相似文献
14.
Mehdihasan I. Shekh Kaushal P. Patel Rajnikant M. Patel 《Journal of Polymers and the Environment》2018,26(12):4376-4387
Coaxial electrospinning technique was used to fabricate the core–sheath composite nanofibers of ZnO nanoparticle (Nps) (10%, 20% w/w) doped polymethyl methacrylate (PMMA) (as sheath) and polyvinyl alcohol (PVA) (as core). Fourier transform infrared (FT-IR) spectra were confirmed the weak forces arise between ZnO Nps, PMMA and PVA matrixes. The hexagonal (wurtzite) structure of ZnO Nps with ~?30.8 nm of diameter was confirmed from the X-ray diffraction pattern. The morphology and microstructure of core–sheath composite nanofibers were confirmed from the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is clearly seen from the TEM images that the PMMA encapsulate the PVA core. Core–sheath composite nanofibers were assessed against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria through quantitative, disk diffusion and viable cell count methods. It was found that ZnO Nps doped core–sheath nanofibers were effectively inhibit the growth of gram positive bacteria, B. subtilis. 相似文献
15.
Meriem Fardioui Abdelhamid Stambouli Taoufik Gueddira Abdelouahed Dahrouch Abou El Kacem Qaiss Rachid Bouhfid 《Journal of Polymers and the Environment》2016,24(4):356-362
The aim of this investigation was to extract nanocrystalline cellulose (NCC) from Moroccan Doum fibers (Chamaerops humilis) by chemical treatment to examine their potential for use as reinforcement fibers in bionanocomposite applications. The chemical composition, morphological and structural properties of the Doum fibers was determined at different stages of chemical treatment. Morphological (transmission electron microscopy and scanning electron microscopy), structural characterization (X-ray diffraction, Fourier transformed infrared), thermal characterization (thermogravimetric analysis). The suspension electrostatic stabilization (zeta potential) of NCCs was also carried out. The results of these characterization analysis found that average size of the NCC is 220 nm in length and 11 nm in diameter, with high crystallinity index (93 %), a thermal stability comparable to that of untreated Doum fibers (degradation temperature 340 °C), which is reasonably promising for the use of these nanofibers in reinforced-polymer manufacturing, and a good stability in water suspension that it allows their utilization such as reinforcement of the water-soluble polymers to prepare the bio-nanocomposite. 相似文献
16.
Rajeev Jindal B. S. Kaith Rachna Sharma 《Journal of Polymers and the Environment》2018,26(3):999-1011
In the present study, the flocculation behavior of crosslinked copolymer GrA-cl-poly(AAm) hydrogel has been studied for the removal of turbidity from waste water. Sodium borohydride has been used for the reduction of the Gum rosin acids by which it gets converted into rosin alcohols. The reduced Gum rosin alcohol was crosslinked by the use of MBA and copolymerized with acrylamide using KPS as a redox initiator. Synthesized sample was then optimized for reaction conditions like reaction time, reaction temperature and the amount of solvent, monomer concentration, initiator concentration and pH of the reaction medium in order to get maximum percentage swelling. Synthesized samples were characterized using Fourier transform infrared spectroscopy, scanning electron of microscopy and X-ray diffraction techniques. Response surface methodology (RSM) based central composite design was used to study the effect of pH of swelling medium and temperature to maximize the percentage swelling. A statistical model (ANOVA) predicted pH 7.0 and temperature 40?°C as optimum operating conditions in order to get maximu swelling. GrA-cl-poly(AAm) hydrogel was found to be pH and temperature sensitive. Kaolin has been employed as a coagulant. The flocculation efficiency of the synthesized polymer was studied as a function of polymer dose, temperature and pH of the solution. GrA-cl-poly(AAm) observed to show maximum flocculation efficiency (95%) with 70mgL?1 polymer dose in pH 5.0 at 30?°C. The adsorption capacity of malachite green dye removal (95%) was also studied with this synthesized polymer. The results validate that GrA-cl-poly(AAm) hydrogel has significant flocculation and dye removal properties and can be employed as an effective and low-cost material for removal of impurities from waste water. 相似文献
17.
In this study we investigated the role of the water content of extrudates had in foaming capacity and searched for the water
content giving the greatest expansion of starch extrudates. Porous structures based on potato amylopectin starch were prepared
by extrusion followed by a microwave foaming process. Starch was first extruded with water, in order to incorporate water
in the granular structure and achieve gelatinization. Extrudates were conditioned at humidities ranging from 11% to 97%. The
water content in the starch extrudates was studied by a water vapor sorption isotherm study. Extrudates were analyzed with
light microscopy and wide angle X-ray scattering studies to determine degree of crystallinity. In the second step, extrudates
were foamed in a microwave oven. As the water started to boil, it acted as a blowing agent, leaving a porous closed-cell starch
structure. The densities and the expansion ratios of the foamed samples are determined. Porosity was studied with environmental
scanning electron microscopy. Mechanical properties as a function of the surrounding humidity were analyzed with dynamic mechanical
analysis. We found that the maximal degree of expansion was in extrudates conditioned at 33% and 54% RH and having water content
of 11.2% and 13.4%, respectively. This level of water is sufficient to expand the extrudate to a maximum level but not high
enough to plasticize the starch and cause cell collapse after treatment. 相似文献
18.
Jesús Ambrosio-Martin María José Fabra Amparo López-Rubio Giuliana Gorrasi Andrea Sorrentino Jose M. Lagaron 《Journal of Polymers and the Environment》2016,24(3):241-254
The aim of this study was the assessment of high energy ball milling technique to develop poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanocomposites containing bacterial cellulose nanowhiskers (BCNW). Crystallization behaviour of PHBV/BCNW nanocomposites was studied under non-isothermal and isothermal conditions using differential scanning calorimetry. The changes in PHBV crystalline structure were also studied using X-ray diffraction. The results confirmed that BCNW acted as nucleating agents and, hence, favored the crystallization of the PHBV. The oxygen permeability of the nanocomposites was reduced by ~22 % when compared to that of the neat PHBV. This work provides a new insight into the development of polyhydroxyalkanoate composites by means of the high energy ball milling technique. 相似文献
19.
Patrícia Moraes Sinohara Souza Nádia Aline Corroqué Ana Rita Morales Maria Aparecida Marin-Morales Lucia Helena Innocentini Mei 《Journal of Polymers and the Environment》2013,21(4):1052-1063
In this study, nanocomposites of PLA and organoclays Cloisite 20A and Cloisite 30B were prepared by the melt intercalation method and the obtained samples were characterized by transmission electron microscopy (TEM). Since composting is an important proposal to the final disposal of biopolymers, the influence of clays on the hydrolytic degradation process of PLA was evaluated by visual analysis and monitoring of molecular weight after periods of 15 and 30 days of degradation in compost. After degradation of the materials in composting environment, the evaluation of cytotoxic, genotoxic and mutagenic effects of compost aqueous extract was carried out using a bioassay with Allium cepa as test organism. The TEM micrographs permitted the observation of different levels of dispersion, including exfoliated regions. In the evaluation of hydrolytic degradation it was noted that the presence of organoclays can decrease the rate of degradation possibly due to the barrier effect of clay layers and/or the higher degree of crystallinity in the nanocomposite samples. Nevertheless, even in the case of nanocomposites, the molecular weight reduction was significant, indicating that the composting process is favorable to the chain scission of PLA in studied materials. In the analysis performed by the bioassay using A. cepa as test organism, it was found that after degradation of the PLA and its nanocomposites the aqueous extract of compost samples induced a decreasing in the mitotic index and an increasing in the induction of chromosomal abnormalities. These results were statistically significant in relation to the negative control (distilled water). By comparing the results obtained for the nanocomposites in relative to pure polymer, there were no statistically significant differences. The types of the observed chromosomal aberrations indicated a possible genotoxic effect of the materials, which may be related to an aneugenic action of PLA degradation products. 相似文献
20.
Anicuta Stoica-Guzun Luiza Jecu Amalia Gheorghe Iuliana Raut Marta Stroescu Marius Ghiurea Mihai Danila Iuliana Jipa Victor Fruth 《Journal of Polymers and the Environment》2011,19(1):69-79
The ability of fungal strains to attack a composite material obtained from poly(vinyl alcohol) (PVA) and bacterial cellulose
(BC) is investigated. The fungal strain tested was Aspergillus niger. This fungal strain was able to change not only the polymer surface from smoother to rougher, but also to disrupt the polymer.
The degradation results were confirmed by visual observations, scanning electron microscopy (SEM) analyses, X-ray diffraction
analyses and FTIR spectra of the film samples. SEM micrographs confirmed the growth of fungi on the composite film surface.
The degree of microbial degradation depends on culture medium and on composition of polymeric materials, especially on PVA
content. The biodegradation process is accelerated by the presence of glucose in the culture medium as an easily available
carbon source. 相似文献