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The novel controlled release fertilizers (CRFs) were physically prepared by coating the conventional fertilizers with the thermosetting resin such as epoxy or unsaturated polyester resin. The incorporation of additives not only decreased the cost of the coating materials epoxy resin, but also greatly improved the controlled release behavior of CRFs. The microstructure and the controlled release properties of CRFs were discussed in detail in this article. The stated release time of CRFs reached the maximum value of 116 d only at the coating rate of 5.3%, and the SEM image also showed that the coating materials have a very dense structure with the thickness of 50 µm or so. The results indicated that the low-cost CRFs products from the thermosetting resin are expected to use in agricultural and horticultural applications. [ABSTRACT FROM AUTHOR]

In this work, thermoplastic starch-clay composite films were prepared via solution casting method. The use of acid-modified clay including kaolinite (HKAO) and vermiculite (HVER) improved the thermal properties of starch matrix. The structure of films was investigated and characterized by XRD and SEM techniques. The results showed that the well-dispersed clay particles were distributed in the starch matrix. According to TGA, DSC study and water absorption testing, the films with acid-modified clay exhibited higher water resistance and thermal properties compared to those of films containing pristine clay. These results provide the important information with using acid as the clay modifier to obtain starch-based materials with higher performance. [ABSTRACT FROM AUTHOR]

The poly(methyl methacrylate)/clay (PMMA/clay) composites were prepared with the different grafted clay, such as sepiolite fiber, vermiculite and Layered double hydroxides (LDH). These clays modified by grafting of vinyltriethoxysilane (VTS) with a double bond onto the clays surface were used as fillers for PMMA. The morphology of clays and composites were determined by Fourier transform infrared spectroscopy (FTIR). Moreover, the thermal degradation behavior was explained by thermogravimetric analysis (TGA). The three grafted clays improved the thermal stability of PMMA composites as a different level. [ABSTRACT FROM AUTHOR]

The preparation of surface-modified layered double hydroxides/unsaturated polyester (LDH/UP) nanocomposites were performed. By in situ coprecipitation, LDHs, modified through grafting of vinyltriethoxysilane (VTS) carrying a double bond using the anionic surfactant sodium dodecyl sulfate (SDS), were used as nanofillers for unsaturated polyester (UP). The morphology of LDH and nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM). Moreover, the thermal properties were determined by thermogravimetric analysis (TGA) and thermal degradation mechanism was discussed. [ABSTRACT FROM AUTHOR]

A novel active food packaging film was developed by casting a corn starch/tea polyphenol (TP)-loaded porous starch (PS, obtained by enzymatic hydrolysis) film forming solution, with the latter helping to regulate the slow release of TP. Results showed that PS had a favorable TP adsorption capacity, and the casted films had a homogeneous distribution of the formulation components. Likewise, the active films had good mechanical properties, UV barrier properties, thermal stability, and excellent antioxidant properties. The slow release of TP from the films was sustained, which is a desired characteristic for extending the protection afforded by the active film to the food under consideration. • Porous starch (PS) was prepared by enzymatic hydrolysis. • Slow-release active packaging films were developed by solution casting technique. • PS had outstanding tea polyphenol (TP) adsorption capacity. • Corn starch (CS)-PS films showed slower TP release than films made from CS alone. • All the measured properties were improved in CS-PS films compared to CS films. [ABSTRACT FROM AUTHOR]

A new nanocomposite coating was synthesized by MMT and polyurethane for controlled-release fertilizers (CRFs). The structure and properties of samples were characterized. The nutrient release behavior of nanocomposite-coated fertilizers (MPUs) and polyurethane-coated fertilizers (PU) in water and in soil were determined. SEM and TEM exhibited good dispersion of MMT lamellae in the MPU coatings. The results also showed that the water contact angle of the MPU coating was greatly improved, the water absorption was reduced by 65.7%, and the coating porosity was reduced by 30.0%. In addition, MPUs exhibited longer nutrient release longevity than that of PU (26 days), especially MPU with 5% MMT (90 days). Therefore, MPUs with excellent properties can provide information for the development of CRFs. [ABSTRACT FROM AUTHOR]

The anthocyanin-rich litchi shell extract (LE) was mixed with the matrix to prepare active/intelligent food packaging composite films. The microstructure and properties of composite films were characterized. The results showed that the composite films incorporated with LE had texture-oriented layered, compact, uniform cross-sections. The composite films with LE showed different degrees of red. The composite films had similar water vapor transmission rates (1.62–1.65 × 10−12 g·cm/cm2·Pa·s). However, gelatin/chitosan/polyvinyl alcohol/litchi shell extract (Gel/Csa/PVA/LE) film had better UV blocking rates (0–20 %), the best tensile strength (18.6 MPa) and elongation at break (116%). When the composite films monitored for fish freshness at 4 °C (10 d) and 25 °C (3 d), the Gel/Csa/PVA/LE film had the pH sensitivity to show an obvious color change at 25 °C, 1th day. The results suggested that the Gel/Csa/PVA/LE film could be applied to intelligent food packaging film to indicate the freshness of fish. [Display omitted] • A novel active and intelligent food packaging composite film incorporated with litchi shell extract was prepared. • Litchi shell extract had excellent antibacterial properties. • Litchi shell extract had extremely high UV shielding properties. • The composite film with litchi shell extract had outstanding mechanical properties. • The intelligent packaging film with litchi shell extract could be used as pH indicator of fish freshness. [ABSTRACT FROM AUTHOR]

Slow release active packaging films can realize the sustained release of active agents and prolong the shelf life of food. For this aim, a novel slow release active polyvinyl alcohol (PVA) film was developed by using solution casting method. With porous starch loaded with tea polyphenols (PSTP) as core material and maltodextrin (MD) as wall material, PSTP@MD microcapsules were prepared using freeze drying method and used as slow release carrier of tea polyphenols (TP) in the active films. The interactions between PSTP@MD microcapsules and PVA molecular chains were physical interactions. In addition, the relative crystallinity of the slow release active films was reduced to 23.74 %. The addition of PSTP@MD microcapsules can enhance the ductility of active films and reduce the water content and swelling degree of active films by 46.74 % and 54.38 %, respectively. Moreover, the thermal stability, water vapor and ultraviolet barrier properties of active films were promoted. The transparency and antioxidant activity of active films was high, and the radical scavenging activity of active films was 58 %. The encapsulation of TP with PSTP@MD microcapsules can realize the slow release of TP. The slow release active films had antioxidant activity and sustained release properties, which could be used as an active packaging film to extend the shelf life of food. [Display omitted] • Porous starch loaded with tea polyphenols (TP) was used to prepare microcapsules. • PVA and microcapsules were used to prepare active packaging film (PPMF). • Adding microcapsules can improve the ductility and thermal stability of film. • The water vapor and ultraviolet barrier properties of PPMF are enhanced. • The release of TP is sustained and the antioxidant activity of PPMF is good. [ABSTRACT FROM AUTHOR]

In this study, anthocyanin from Garcinia mangostana shell extract (Mse) was used as pH indicator to prepare intelligent carboxymethyl cellulose (CMC) based composite films. The structure and properties of the CMC-based composite films were characterized and discussed in detail. Results showed that the CMC-based composite films with Mse had excellent mechanical, antibacterial and antioxidant abilities. Especially, the carboxymethyl cellulose/corn starch/ Garcinia mangostana shell extract (CMC/Cst/Mse) composite film had best mechanical properties (20.62 MPa, 4.06 % EB), lowest water vapor permeability (1.80 × 10−12 g·cm/(cm2·s·Pa)), excellent ultraviolet (UV) blocking performance, and the best antibacterial and antioxidant abilities. The pH sensitivity of composite films which had Mse obviously changed with time when the fish freshness was monitored at 25 °C. Given the good pH sensitivity of the composite films, it had significant potential for application of intelligent packaging film as a food packaging material to indicate the freshness of fish. [Display omitted] • The anthocyanin in Garcinia mangostana shell extract (Mse) had various bright color changes in pH solution. • The addition of Mse did not affect the thermal stability and crystallinity of the CMC-based films. • The CMC-based composite films with Mse had excellent optical and mechanical properties. • The CMC-based composite films with Mse had excellent antioxidant and antibacterial activity. • The CMC-based intelligent packaging film with Mse could be used as pH indicator of fish freshness. [ABSTRACT FROM AUTHOR]

• The bio-based polymer film was prepared using starch-based polyol and castor oil. • The starch-based polyol generated micropores in the film, regulated early N release. • Mutual modification regulated nutrient release more accurately. • The bio-based coating material was degradable and has no toxic effect to seeds. Due to the poor controlled release ability, bio-based materials are difficult for large scale application on controlled release fertilizers (CRFs). Starch-based polyol (SP) and castor oil (CO) were mutually modified, and a cross-linked polymer film was formed on the surface of urea by in-situ reaction, which improved the slow release ability of the bio-based material. The results showed that increasing the CO ratio reduced porosity of coating and prolonged the nitrogen (N) release period, while the SP changed the high-temperature wrinkle characteristics and regulated the early N release rate. The mutual modification achieved an ultra-long release period of bio-based CRUs for 7 months. The degradation rate during nine months of bio-based coatings (5.05 %) was significantly higher than that of petroleum-based (3.74 %), and the coating was non-toxic to rice seeds. Mutual modification provided a safe and effective solution for the preparation of bio-based CRFs with long-term controlled release capability. [ABSTRACT FROM AUTHOR]

The paper presents a new controlled release fertilizer coated by dimer acid-based polyurethane (PU). The structure and property of the sample were characterized. Results indicated that the polyether polyol modified PU (MPU) coating reduced water absorption rate by 72.1% after 29 d, and increased the cross-linking density by 23%, and decreased the coating porosity by 26%, Moreover, MPUFs and PUFs both exhibited excellent nutrient controlled release abilities, especially the MPUF possessed longer nitrogen release longevity (118 d,131%) compared with PUF (51 d). Thus, the high-performance MPUFs with environmentally friendly and excellent controlled release could be widely applied to agricultural fields. [ABSTRACT FROM AUTHOR]

Nearly 1 billion tons of bagasse are discarded annually in the production process. In this work, a novel controlled release fertilizer was successfully produced by coating urea particles with bio-based epoxy (EPCU). The bio-based epoxy coating was synthesized from the liquefied bagasse (LB) and bisphenol-A diglycidyl ether (BDE) with the different mole ratios of LB to BDE. The chemical structure and microscopic morphology of EPCU were examined by FTIR, 1 HNMR, SEM. The nutrient release behaviors and mechanism of EPCUs were also discussed in detail. Results showed that EPCU3 improved the thermal stability by 60.3 °C (T 10% ), increased the nutrient release longevity by 12 times, and raised the water contact angle of surface by 12%, and then significantly slowed the nitrogen release rate of the EPCU. This work indicated that the environment-friendly EPCU with superior controlled release properties could be especially useful in horticultural and agricultural applications. [ABSTRACT FROM AUTHOR]

Alkali-hydrolyzed lignocellulose was liquefied into polyols by acid-catalyzed dissolution, and then cross-linked with castor oil to prepare bio-based cross-linked polyurethane. Then, bis (2-hydroxyethyl) disulfide (SS) with self-healing function was used to reduce foaming in the curing process of polyurethane coating. Afterwards, disulfide bond modified cross-linked bio-based polyurethane coating (BCSPU) was applied to controlled-release urea (CRU). The results of excitation-emission matrices indicated that SS made the coating smoother and denser and preventing the release of non-film-forming substances. Cross-linking modification technology significantly extended the controlled release longevity of CRU by 77.3%, and the self-healing modification further prolonged the nitrogen release longevity by 61.5%. In addition, modified coating materials were non-toxic to wheat seeds and easily biodegradable in the soil. Cross-linking, self-healing modified controlled-release urea has enormous application potential in sustainable agriculture. [Display omitted] • Bio-based polymer made from corn stover-derived lignocellulose and castor oil. • Two bio-based polyols regulate the precise nitrogen release of CRFs. • Thiol modification densifies the coating and reduces the impurity dissolution. • Bio-based coating materials are easily degradable and harmless to wheat seeds. [ABSTRACT FROM AUTHOR]