交联壳聚糖/蒙脱土复合膜的制备及性能研究

以壳聚糖（CS）为基质材料，蒙脱土（MMT）为填料，采用戊二醛（GA）交联改性并结合溶液插层法制备了交联壳聚糖/蒙脱土（CS/GA/MMT）复合膜。通过扫描电子显微镜、X射线衍射仪、红外光谱仪及热重分析仪对复合膜的结构进行了表征，考察了MMT用量对复合膜的吸水性能、水蒸气阻隔性能和力学性能的影响。结果表明，交联改性CS可提高CS膜的耐水性，CS/GA膜的吸水率较CS膜降低了9.6 %；MMT可提高复合膜的耐水性、水蒸气阻隔性能、力学性能和热稳定性；当MMT的用量为CS质量的5 %时，复合膜的各项性能较好，吸水率、水蒸气透过率和断裂伸长率较CS膜分别降低了37.3 %、36.7 %和41.9 %，且拉伸强度提高了160.5 %。     

Dynamic mechanical properties of polystyrene–aluminum nitride composite

A composite of aluminum nitride (AlN) particles dispersed around polystyrene matrix particles was synthesized in this study. The purpose of using this microstructure is to improve the thermal properties of a polymer at a low filler content with a minimal increase in the dielectric constant of the polymer composite to meet the material requirements for electronic packaging. The dynamic mechanical properties of this type of polystyrene–AlN composite were investigated here. The experimental results indicate that the dynamic mechanical property of the polystyrene–AlN composite is a function of the polystyrene particle size, AlN filler concentration, and temperature under this dispersion state. The addition of an AlN concentration into polystyrene increases both the storage modulus and the α‐transition temperature. The smaller polystyrene particle size gives a higher storage modulus and damping peak. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1348–1353, 2000     

Enhancement of basic properties of polysaccharide-based composites with organic and inorganic fillers: A review

The global shift towards biodegradable composite has made polysaccharides a green alternative to synthetic polymers owing to their biocompatibility, sustainability, and ecofriendly biomaterials. Despite the limitations in their applications, many studies have validated the effectiveness of using organic or inorganic fillers to ameliorate their mechanical and barrier properties. However, the understanding of how polysaccharides matrix is enhanced by fillers is still inexplicit. Hence, it is imperative to review the effects of using inorganic and organic fillers in some prominent polysaccharides in terms of mechanical and water barrier properties while taking into account the function of filler morphology, size and loading. Although it is intricate to indicate the best filler used for each of the polysaccharides matrices, this review served as a “food for thought” on the established works of enhanced-matrix filler combinations aimed at improving the mechanical and barrier properties of biodegradable films based on neutral or negatively charged polysaccharides-based composite films for potential application in food packaging, agriculture, biomedicine and constructions sector. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47251.     

Design of Alginate-Based Bionanocomposites with Electrical Conductivity for Active Food Packaging

Bionanocomposite materials have been designed as a promising route to enhance biopolymer properties, especially for food packaging application. The present study reports the preparation of bionanocomposite films of alginate with different loadings of pure reduced graphene oxide (rGO) or of mixed zinc oxide-rGO (ZnO-rGO) fillers by solvent casting. Sepiolite is used to make compatible rGO with the hydrophilic matrix. The addition of fillers to alginate matrix maintains the low water solubility promoted by the calcium chloride treatment, and, additionally, they demonstrate a weaker mechanical properties, and a slight increase in water vapor permeability and wettability. Due to the properties of ZnO-rGO, the alginate bionanocomposites show an increase of electrical conductivity with the increase of filler content. While the highest electrical conductivity (0.1 S/m) is achieved by the in-plane measurement, it is in the through-plane measurement the remarkable enhancement of almost 30 times greater than the alginate film. With 50% of ZnO-rGO filler, the bionanocomposites present the highest antioxidant and antibacterial activities. The combination of electrical conductivity with bioactive properties makes these films promising not only to extend food shelf-life but also to allow packaged food sterilization at low temperature.     

Polyethylene with MoS2 nanoparticles toward antibacterial active packaging

Molybdenum disulfide (MoS₂) nanoparticles, obtained from liquid phase exfoliation in the presence of chitosan, were melt mixed with a linear low-density polyethylene (LLDPE) matrix to produce novel antimicrobial active packaging materials. The LLDPE/MoS₂ composites presented exfoliated nanoparticles forming aggregates that are well dispersed in the polymer matrix. These 2D-layered MoS₂ nanoparticles at concentrations of 0.5, 1.0, and 3.0 wt% rendered several functionalities to the LLDPE, as for example an antimicrobial behavior against Salmonella typhi and Listeria monocytogenes bacteria that can be explained not only by the photoactivity of the filler but also by changes in the composite surface. For instance, the composites presented a reduction in the water contact angle (i.e., an increased hydrophilicity) and relevant changes in the surface topography (i.e., reduced roughness) as compared with pure LLDPE. Regarding the barrier properties, while MoS₂ dramatically increased the water vapor permeation (WVP) of the polymer matrix, until 15 times for composite with 3.0 wt% of filler, the oxygen permeation decreased around 25%. All these novel functionalities in the nanocomposites were obtained without significantly affecting the tensile mechanical properties of the pure LLDPE matrix. These results show that MoS₂ is a promising filler for the development of antibacterial active packaging films with behaviors as similar as other 2D-layered fillers such as graphene derivatives.     

Effects of a liquid metal co-filler on the properties of epoxy/binary filler composites

Liquid metals (LMs) with high fluidity and high thermal conductivity (TC) are receiving considerable attention in the research on thermal management polymer composites as alternatives to conventional rigid solid fillers or as co-fillers to overcome the trade-off between TC and composite processability at high filler loads. While most previous studies have investigated the effects of LM fillers in soft elastomeric matrices, their effects on the composite properties with rigid matrices, such as epoxy-based polymers, have not been discussed extensively. Herein, we investigated the effects of LM eutectic Ga-In (EGaIn) as a co-filler on the properties of rigid epoxy-based composites with a binary filler (Al₂O₃/EGaIn) system. The increase in the volume fraction of LM fillers significantly improves the processability of uncured precursor composites but markedly decreases the mechanical strength of the cured composites at their high loads—the latter effects have rarely been examined in previous studies. However, with adequate LM loads, the composites exhibited superior mechanical properties compared with the all-solid-filler system, withstanding a surprisingly high compressive load (~100 kN) under which the all-solid-filler system fractured. Furthermore, the epoxy/binary filler composites exhibited reasonably high TC values (~1 W/mK) comparable to that of commercial epoxy molding compounds, suggesting their potential applicability for electronic packaging.     

Microwave Dielectric Properties of Rutile Filled PEEK Composites

Ceramic-filled PEEK composites were prepared by sigma mixing followed by thermolamination. Rutile-grade titanium dioxide, particle size less than 5 μm, was used as the particulate filler in the PEEK matrix to tailor the dielectric properties of the composite matrix. The dispersion of the particular filler in the PEEK matrix was studied using scanning electron microscopy. The dielectric properties of the PEEK/TiO₂ composite materials were measured in the low frequency region up to 13 MHz using an impedance analyzer. Dielectric properties in the microwave region were measured using cavity perturbation technique to evaluate the use of the composites as packaging material. Experimental results were compared with theoretically predicted values using the Lichtenecker equation. The present study shows that temperature-stable packaging materials can be realized in the PEEK/TiO₂ systems by judiciously controlling the ceramic filler concentration.     

Raw and chemically treated bio-waste filled (Limonia acidissima shell powder) vinyl ester composites: Physical,mechanical, moisture absorption properties,and microstructure analysis

The rapid growth of environmentally sustainable and eco-friendly materials tends to the utilization of biowastes as filler in polymer matrix composites. The particulate composite with improved wettability of fillers and advanced approach can evolve polymer composites that exhibit promising applications in packaging, automobile, marine, construction, and aerospace. In the present work, one of the biowaste fillers were synthesized from Limonia acidissima shells via a top-down approach (pulverizing) and the surfaces were chemically modified using sodium hydroxide (NaOH) before they were used as fillers in vinyl ester polymer composites by different weight percentage (0, 5, 10, 15, and 20 wt%). The prepared particulate composites were characterized by mechanical properties, moisture absorption behavior, and morphology. At different filler loading the tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, hardness, density, and moisture intake tests were performed. The results reveal that the properties increased for composites filled with alkaline treated fillers for the same filler loading and found to be higher at filler loading of 15 wt%. The morphological analysis confirms the better interfacial bonding between alkali-treated particles and matrix due to the removal of non-cellulose materials from the surface of the particles.     

Orange peel waste from juicing as raw material for plastic composites intended for use in food packaging

Utilization of orange peel (OP) from the juicing industry as filler material within a polymer matrix can add value to this agricultural waste and reduce dependence on nonrenewable resources. This study aims to investigate the impact of OP filler's physical characteristics including size, loading, and retention/removal of zest on plastic properties of interest for food packaging. Linear low-density polyethylene (LLDPE) is selected to produce plastic composites due to its widespread use in food packaging. Eight different LLDPE/OP sheets from combinations of different OP characteristics are examined. Results show that OP particle sizes of 75–177 μm without zest at 0.4-g loading improve thermal stability, color, dispersion, tensile strength, modulus of elasticity, and elongation at break as well as reduce air bubble formation and OP agglomerate sizes in LLDPE/OP composites. Results show a promise in utilization of OP fillers to produce a composite comparable to neat LLDPE and composites with UV-blocking properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48841.     

Development of sulfated polysaccharide-based film reinforced with seaweed biomass-derived nanofillers

Cling films and single-use plastics are difficult to recycle and cause major environmental pollution, leading to an increase in microplastics in nature. To overcome this issue, biodegradable films are being explored more extensively. Seaweed is gaining prominence in the food packaging sector since it is beneficial in all aspects. Two fractions of Indian brown seaweed Sargassum wightii, biopolymer (sulfated polysaccharide [SP]) as base material and nanofillers (cellulose nanocrystals [CNC]) as reinforced filler are employed to develop a sustainable cling film for food packaging. This cellulose filler can be isolated from solid seaweed biomass after the polysaccharide extraction and converted into nanoform using the response surfaces method (RSM) to maximize the yield of CNC. The objective of this research is to construct seaweed-based biodegradable nanocomposite films and to examine their improved properties. It exhibited a gradual decrease in water absorption and water vapor permeability (WVP), along with better wettability, mechanical, and antioxidant properties, and thermal analysis compared with the control SP film. The degradation rates of the films were analyzed using the soil-burial method. According to the results obtained, it is suggested that CNC can be utilized as a functional filler to improve the qualities of seaweed-based cling films.     

Mechanical and Physical Properties of Cassava Starch-Gelatin Composite Films

The effect of gelatin concentrations on the mechanical properties and solubility of cassava starch-based films containing glycerol was studied. Increasing concentration of gelatin increased tensile strength but reduced elongation at break and water solubility of the composite films. Films containing 30% gelatin showed the highest tensile strength. Fourier transform infrared spectroscopy (FT-IR) spectra indicated intermolecular interactions between cassava starch and gelatin in composite films. The X-ray diffraction (XRD) technique demonstrated pseudo-crystalline regions in the cassava starch-gelatin composite films, and it is supposed that the interactions between cassava starch and gelatin were shown in the diffractograms by shifts in scattering angles. The differential scanning calorimetry (DSC) thermograms and scanning electron microscopy (SEM) micrographs confirmed homogeneity of cassava starch-gelatin films. Cassava starch-gelatin composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low-moisture food and pharmaceutical products.     

硅藻土/白炭黑复合填料的补强性研究

为拓展硅藻土在高分子复合材料中的应用,将硅藻土/白炭黑填充到天然橡胶/丁苯橡胶/顺丁橡胶中制备了复合材料。通过RPA2000和扫描电镜分析了复合填料的Payne效应和分散性,考察了硅藻土用量对复合材料工艺性能、力学性能、耐磨耗性能影响。结果表明:少量硅藻土的加入有利于白炭黑在橡胶中的分散,能降低复合材料的门尼粘度和Payne效应,提高复合材料的硫化速度,缩短硫化时间,复合填料的补强效果较好;随着硅藻土用量的增加,复合填料容易聚集,其力学性能呈下降趋势,而磨耗性能变化不大;当硅藻土用量10~20份时,复合材料的综合性能最好。     

电子塑封材料研究进展

简述了电子塑封材料的特点.概括了封装材料常用的酚醛树脂(PF)、苯并噁嗪树脂(BOZ)、氰酸酯树脂(CE)、环氧树脂(EP)、聚酰亚胺(PI)、双马来酰亚胺(BMI)、聚苯醚(PPO)等几种树脂基体的性能.并根据现阶段电子封装材料的发展要求,重点叙述SiO<,2>、Si,N<,4>、Al<,2>O<,3>,及AIN等填...     

High electromagnetic interference shielding effectiveness in MgO composites reinforced by aligned graphene platelets

Graphene has been considered as an excellent filler to reinforce ceramics with enhanced properties. However, the uniform dispersion and controlled orientation of graphene sheets in a ceramic matrix have become major challenges toward higher performance. In this paper, we prepared MgO matrix composites with parallel graphene layers through the intercalation of the precursor into expandable graphite. We obtained a high electromagnetic interference (EMI) shielding effectiveness of ~30 dB, due to the multiple reflections and absorptance of electromagnetic waves between the parallel graphene layers. The hardness and strength of the MgO composite were also increased by introducing parallel graphene layers. All these properties suggest that the graphene/MgO composite represents a promising electromagnetic shielding material.     

Multifunctional and pH-responsive dialdehyde cellulose/polyvinyl alcohol composite film reinforced with curcumin

The rational design of food packaging films with good antimicrobial activity, antioxidant activity, and monitorability is of great importance in intelligent packaging. In this study, an active composite film was prepared by adding curcumin to a dialdehyde cellulose (DAC)/polyvinyl alcohol (PVA) matrix. It was found that the Cur/DAC/PVA composite film exhibited optimal tensile strength at 30°C. The tensile strength of the composite film control PVA/DAC film was observed to increase by 176% due to the affection of hydrogen bonding. Under the influence of curcumin, the UV barrier property and antioxidant activity of the composite film were significantly increased, and the ABTS⁺• was removed by 0.5Cur/DAC/PVA up to 88% at low curcumin content. The water solubility and water vapor permeability were both reduced to some degree. It was also observed that composite film displayed an inhibitory effect on the growth of Staphylococcus aureus bacteria. Meanwhile, the Ritger and Peppas release model was used to study the release control capability of curcumin. Furthermore, the Cur/DAC/PVA composite film demonstrated excellent color response to pH, which it they could be used for intelligent packaging with real-time visual monitoring.     

Nonwoven viscose fabric-polyvinyl alcohol based flexible composite

Development of ecofriendly packaging materials is still a challenging area. Researchers are continuously working to improve the mechanical and barrier properties of the different polymers which are used in the packaging industry. Selection of reinforcement and matrix for any composite are based upon end use applications. The novelty of the work is development of fully biodegradable, flexible, lightweight biocomposite by reinforcing needle punched flexible nonwoven viscose fabric to the PVA solution. The effect of PVA concentration and areal density of viscose fabric on the properties of prepared composite is examined. The composite thus prepared is assessed in terms of mechanical, thermal, breathability, and UV blocking properties. The nonwoven viscose-PVA composite shows excellent improvement in tensile strength of 100% to 300% with respect to PVA film of equivalent concentration for two different areal densities of viscose fabric. The composite also exhibits improved thermal stability and UV blocking property with respect to parent components. However, a reduction in flexibility (with respect to PVA film) as well as breathability (with respect to viscose fabric) of the composite is observed. Based upon the improved performance of the viscose-PVA composite in terms of mechanical properties, UV and water vapor permeability, it seems that the composite has a strong potential for application in the packaging sector as a flexible as well as biodegradable composite.     

基于海藻酸钠抗菌材料制备及应用的研究进展

概述了静电纺丝技术的原理及其在生物性纳米复合材料制备过程中的作用.该技术可将多种材料以不同的方式复合到同一根纤维中,使得纤维又增添了多种新的功能,因此其在多功能复合材料制备方面的应用广受关注.同时由于海藻酸钠纳米材料具有良好的理化性质、功能特性、生物相容性及特殊的纳米效应,利用静电纺丝技术将高效抗菌剂均匀分布到海藻酸钠材料中制备成抗菌复合薄膜,使其在食品包装、创伤敷料、药物载体及组织工程支架等方面体现出了重要的应用价值.此外,本文还在该技术的基础上,提出了关于静电纺丝制备海藻酸钠抗菌复合薄膜过程中改性剂的优化、抗菌剂的选择等方面的问题,并展望了基于静电纺丝技术的海藻酸钠抗菌复合薄膜的应用前景.     

Influence of Hybrid Cellulose/Bentonite Fillers on Structure,Ambient, and Low Temperature Tensile Properties of Thermoplastic Starch Composites

Thermoplastic starch (TPS) composites incorporating bentonite/cellulose (Bent/Cellulose) hybrid fillers in different ratios were prepared by film casting. Ultra-sonication was done to promote good dispersion of filler in the host TPS and enhance the filler-matrix interactions. Ultra-sonicated fillers resulted in superior improvement in the tensile properties when the samples preconditioned at both ambient and 2°C. Upon preconditioning at 2°C, the TPS composite containing the ultra-sonicated hybrid bent/cellulose in 80:20 ratio displayed the greatest tensile properties achievement among all the tested materials. These could be due to the effect of low temperature interactions between the starch, plasticizers, and the hybrid fillers. Differential scanning calorimetry analysis proved the changes in the crystallinity and dynamic characteristic of the TPS molecular chains which benefit in enhancing the biopolymer elongation at break and toughness, even when stored at refrigerated condition. In summary, the TPS/bent/cellulose composite has potential to be further developed for refrigerated food packaging application. POLYM. ENG. SCI., 60:810–822, 2020. © 2020 Society of Plastics Engineers     

Mechanical and morphological characterization of PVC plastisol composites with almond husk fillers

The present study develops new composite materials derived from environmentally friendly material, based on lignocellulosic fillers combined with a thermoplastic matrix. Almond husk, obtained as a by‐product of the agri‐food industry, has been used as a filler, combined with PVC thermoplastic matrix. This composite type (lignocellulosic material/thermoplastic matrix) is the object of this work for the advantages that it offers in environmental protection terms. With a view to identifying the degree of influence of filler amount, plasticizer concentration, and filler particle size on the properties of this new composite, we tested its mechanical properties and analyzed tensile fracture surfaces using scanning electron microscopy. POLYM. COMPOS., 28:71–77, 2007. © 2007 Society of Plastics Engineers     

SiO2粒径对环氧树脂复合材料介电性能的影响

将不同粒径的SiO2微球与环氧树脂复合,制备用于直流特高压关键设备的高性能环氧绝缘复合材料,分析了其体积电阻率、介电常数与损耗,考察了SiO2微球对复合材料主要电气性能的影响;通过扫描电镜、动态热分析SiO2微球与环氧树脂的界面作用. 结果表明,不同粒径的SiO2微球均对环氧树脂复合材料性能有改善作用,添加100 nm SiO2的复合材料提升效果最显著,体积电阻率从1.87′1017 W×cm提至3.24′1017 W×cm,介电常数实部从10.99降至4.92,玻璃化转变温度从104.9℃升至106.4℃,这是因为100 nm SiO2微球表面吸附水分少、与树脂作用力强.