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An atmosphere within a package affects the metabolic process of food and the microbial growth of fresh products and has a vital role in preserving food. It depends on the membrane's specific gas permeability and selectivity to generate a desirable atmosphere for storage. In this study, triblock poly(l-lactic acid‑d-ɛ-caprolactone) (PLDC) copolymers and three-arm poly(l-lactic acid-g-ɛ-caprolactone) (PLGC) star copolymers were synthesized, in which a microphase-separated morphology of sea-island structure was established in PLGC membrane as a gas "fast permeation channel" for regulating CO

Nanocomposite hydrogel composed of Poly N-isopropylacrylamide (PNIPAM), poly N-tert-Butylacrylamide (PBAM) and poly acrylic acid (PAA) was synthesized by free radical polymerization, and then thymol was embedded in it, to design an active antibacterial material that could control release. The characterization of products used SEM, AFM, FTIR, Zeta sizer to analyze the sensitivity of nanoparticles to pH, temperature and salt ions, and the agar diffusion method was used to determine the antibacterial effect of the polymers. The results showed that nanoparticles had pH, temperature and salt ion responsiveness, PNIPAM/PBAM (65:35) nanoparticles loaded thymol had longer release time (more than 24 h) at lower temperature than that (around 6 h) at high temperature. In addition, the nanoparticles could also be adsorbed on the chitosan film, which makes it have a wider range of applications. All thymol-loaded nanoparticles showed antibacterial activity against both B. subtilis and E. coli, while the chitosan film adsorbed nanoparticles showed weak effect, which was related to the controlled and slow release of bacteriostatic agents. Thus, these copolymers have potential value in the development and application of bacteriostatic packaging films for food.

Gas permeability of films is essentially important for fresh products packaging. The flexible poly(e-caprolactone) (PCL) was incorporated into the backbone of poly(L-lactic acid) (PLLA) to improve the flexibility and gas permeability of PLLA. The effects of different PCL middle blocks on the mechanical properties, oxygen (O2), carbon dioxide (CO2) and water vapor permeative properties of PLLA-PCL-PLLA triblock copolymers were evaluated, as well as its preservation effect on strawberry. The results showed that both the PCL and PLLA blocks kept amorphous state, and phase separation occurred in this immiscible system. The PCL play a role of gas passage, the CO2 permeability and CO2/O2 perm-selective ratio of neat PLLA film improved 2–3 times with the incorporation of higher molecular weight PCL. In addition, the PLLA-PCL-PLLA films presented a better toughness after large insertion of flexible PCL. Storing experiments showed that the low O2 and high CO2 atmosphere was established inside the package due to the good gas exchange performance of films. Moreover, strawberries still maintained the good sensory quality and Vitamin C contents on 24th day. Such biodegradable PLLA soft films are of great potential in fresh product packaging.

Blend films with poly(ε-caprolactone)(PCL) and poly(propylene carbonate)(PPC)with thickness of approximately 40 μm and 60 μm, respectively, were prepared using a uniaxial-stretching extrusion process to modify the property of PCL. PCL/PPC blend films with better comprehensive properties with thickness about 60 μm were used for equilibrium-modified atmosphere packaging of button mushrooms at 5 °C. The gas barrier property together with water vapor permeability were evaluated as well as its effects on the shelf life button mushrooms. The results showed that the PCL/PPC20 and PCL/PPC50 blend films have suitable gas barrier property and water vapor permeability, which was helpful to generate an appropriate storage environment and more importantly no condensation occurred in these two packages. The lower weight loss of button mushrooms was observed for PCL/PPC20 and PCL/PPC50 blend films 4.43 and 4.46, respectively. The PCL/PPC blend films was more effective in decreasing the activity of PPO and preserving the color of the button mushrooms. The over market acceptability of button mushrooms packaged in PCL/PPC blend films still maintained good and within the limit of marketability after 17 days of storage.

PLA is widely used in the field of disposable products for its good transparency, high strength, high modulus, and good processing performance. However, the crystallization rate and crystallinity of PLA are weak. In actual production, the PLA products that are typically obtained are amorphous with poor heat resistance, which greatly limits the application range of PLA products. Finding an effective nucleating agent to improve the transparency of PLA has been a hot topic in research. This study found that Cerium fluoride (CeF3) can effectively improve the crystallinity of PLA/CeF3 (P/F) films. When the content of CeF3 in PLA was 1 wt %, the retention ratio of visible light transmittance was 82.36%, the crystallinity was 29.8%, and the tensile strength was 59.92 MPa. Compared to pure PLA, the crystallinity of P/F1 increased by 56% and tensile strength increased by 8.76%. This study provided an alternative scheme that maintained the PLA film’s transparency and improved the crystallinity of PLA, which significantly expanded the application of PLA.

The poly( ε-caprolactone)/silicon oxide (PCL/SiO x)-coated film was prepared by plasma-enhanced chemical vapor deposition of SiO x. The result showed that the PCL/SiO x film presented increased elongation at break and appropriate gas permeability and CO2/O2 permselectivity. The PCL/SiO x film was further used for window packing container of equilibrium-modified atmosphere packaging of fresh cherry tomato. The gas composition within containers depended on the permeability of PCL/SiO x film and respiration of cherry tomato, which finally reached steady states that 4–6% CO2 and 11–13% O2 at room temperature and 2–3% CO2 and 17–19% O2 at 5°C, respectively. High sensory score, firmness, soluble solid concentration, ascorbic acid content, lower weight loss, and retarded respiration climacteric could be found for the cherry tomato packaged by PCL/SiO x film, indicating that delayed ripening, higher nutrient content, and extended shelf life were achieved.

A uniaxial‐stretched poly(ε‐caprolactone)/poly(propylene carbonate; PCL/PPC) composite film was prepared using a twin‐screw extruder, and its utility as an equilibrium‐modified atmosphere packaging (EMAP) film extending the shelf life of garland chrysanthemums stored at 2~4°C was explored. The oxygen, carbon dioxide, and water vapor penetration properties, mechanical properties, and gas permselectivity of PCL/PPC film used to package garland chrysanthemums were determined and compared to those of controlled low‐density polyethylene (LDPE) and PCL films. Physicochemical properties such as package headspace gas composition, weight loss, leaf color, total chlorophyll content, ascorbic acid content, lipid peroxidation extent, and the sensory traits of garland chrysanthemums were investigated over a storage period of 14 days to compare the preservative effects of the various packages. PPC blending decreased the PCL gas and water vapor permeability and slightly increased the CO 2 permselectivity. These effects on gas and water vapor permeability, combined with the effects on gas permselectivity, enhanced preservation of packed garland chrysanthemums. Furthermore, an O2 inner atmosphere level of 2%~5%, and a CO 2 concentration not greater than 8%, was established by the PCL/PPC film in the absence of condensation. The results thus suggest that biodegradable film can be used as an EMAP film to better maintain the quality of freshly harvested garland chrysanthemums and to afford a longer shelf life during cold storage compared to LDPE film. Sensory evaluation indicated that the garland chrysanthemums were market‐acceptable after 14 days of storage; LDPE‐packed chrysanthemums were acceptable only up to 8 days of storage. The film thus improved storage life compared to that afforded by LDPE.

High molecular weight poly(L-lactic acid)-poly(ethylene glycol)-poly(L-lactic acid) (PLLA–PEG–PLLA; PLGL) triblock copolymers with various lengths of the PLLA blocks were synthesized by ringopening polymerization of L-lactide. The amorphous and crystalline PLLA and PLGL films were prepared by hot pressing with different temperature treatments. PLLA and PEG blocks exhibited good miscibility in the amorphous PLGL samples, while phase separation occurred in the crystalline ones. The flexible PEG blocks not only accelerated the crystallization rate of PLLA but also greatly improve its flexibility. The crystallization time of PLGL copolymers shorten to less than 5 min and copolymers showed much better flexibility than neat PLLA, the maximum fracture strain reached about 600% for amorphous sample. The processing time of PLLA was greatly shortened and the brittleness of material was improved.

To clarify the dynamic changes of cell wall metabolism and flavor components in Agaricus bernardii packed with the packaging materials during storage. The polyethylene (PE), poly (butylene adipate-co-terephthalate)/ poly ( l -lactic acid) (ECFPLA) and PBAT/PLLA/ hydrophobic silica (ECFPLASiO2) with a different gas/water vapor permeability were used as equilibrium modified atmosphere packaging (EMAP) materials, and an appropriate gas concentration [O2 (0.01−0.03 %), CO2 (4.58–6.62 %)] was created inside the ECFPLASiO2 packaging, which led to Agaricus bernardii with higher level of cell wall components and lower level of cell wall degrading enzymes during the storage period. For the first time application of HS-SPME–GC–MS on an extract from fresh Agaricus bernardii. The results showed that volatile compounds of fresh Agaricus bernardii mainly consists of alcohols, ketones and aldehydes, with 3-octanol, 3-octanone, 1-octene-3-alcohol and phenylcarbinol being most abundant compounds. During the storage time, the varieties and content of volatile compounds were changed in all treatments. Alcohols, aldehydes, hydrocarbons and esters contents increased during the storage while ketones declined. Among all treatment groups, ECFPLASiO2 group showed higher most abundant compounds and organic acid content. The results suggest that ECFPLASiO2 film could be used to reduce the changes in cell walls and flavor components after harvest and extend the shelf life of Agaricus bernardii.

In this work, poly(L-lactic acid) film was coated with SiOx by the plasma-enhanced chemical vapor deposition with different deposition times. Compared with the neat poly(L-lactic acid) film, the ox...

This work aimed to explore the effect of antibacterial pads containing cinnamaldehyde on the shelf life of cold fresh pork. A nonwovens polyethylene terephthalate (nonwovens PET) was used as the substrate, crosslinked on the surface by β-cyclodextrin embedded with cinnamaldehyde, to prepare the sustained-release antibacterial pad. Cinnamaldehyde in the antibacterial pads can be continuously and uniformly released in a fat food simulant. Antibacterial tests revealed that the antibacterial pads can inhibit the growth of Escherichia coli and Staphylococcus aureus. In combination with the tray packaging, the antibacterial pads were used to preserve cold fresh pork. The results showed that the antibacterial pads can effectively prolong the shelf life of cold fresh pork, and could maintain the quality of the pork. The antibacterial pads could control the sustained-release of cinnamaldehyde, allowing long-term antibacterial effect, with great potential in active packaging to extend the shelf life of cold fresh pork.

A layer of SiOxwas deposited on the surface of poly(L‐lactic acid) (PLLA) film to fabricate a PLLA/SiOxlayered film, by plasma‐enhanced chemical vapor deposition (PECVD) process. PLLA/SiOxfilm showed Young's modulus and tensile strength increased by 119.2% and 91.6%, respectively, over those of neat PLLA film. At 5 °C, the oxygen (O2) and carbon dioxide (CO2) permeability of PLLA/SiOxfilm decreased by 78.7% and 71.7%, respectively, and the CO2/O2permselectivity increased by 32.5%, compared to that of the neat PLLA film. When the PLLA/SiOxfilm was applied to the equilibrium‐modified atmosphere packaging of chilled meat, the gas composition in packaging reached a dynamic equilibrium with 6% to 11% CO2and 8% to 13% O2. Combined with tea polyphenol pads, which effectively inhibited the microbial growth, the desirable color of meat was maintained and an extended shelf life of 52 d was achieved for the chilled meat. The PLLA/SiOxfilm, which is prepared by an advanced technology can be potentially applied for equilibrium‐modified atmosphere packaging to control the gas composition and extend the shelf life of chilled meat.

Poly( l -lactic acid)-poly(ethylene glycol)-poly( l -lactic acid) (PLLA-PEG-PLLA) and poly( d -lactic acid)-poly(ethylene glycol)-poly( d -lactic acid) (PDLA-PEG-PDLA) triblock copolymers having relatively high molecular weights (Mn > 60 kDa) and different lengths of PEG midblock (2–20 kDa) and PLLA, PDLA end blocks (20–45 kDa for each block) were prepared and blended in equal mass. The competing crystallization kinetics, polymorphic crystalline structure, mechanical and thermomechanical properties of PLLA-PEG-PLLA/PDLA-PEG-PDLA blends were investigated and compared with the PLLA/PDLA blend. Both the crystallization rate and stereocomplexation ability of PLLA/PDLA blends were improved after the incorporation of PEG midblocks. The crystallization half-time decreases and the crystallinity, content of stereocomplexes (SCs) enhance as the length of PEG midblock increases or the lengths of PLLA, PDLA end blocks decease. The melt recrystallization from homocrystallites (HCs) to SCs becomes more pronounced with increasing the length of PEG midblocks in the enantiomeric blends. The enhanced SC formation and crystallization rate of PLLA-PEG-PLLA/PDLA-PEG-PDLA blends are attributed to the increased diffusion ability and decreased diffusion pathway of enantiomeric chains. The synergistic effects of stereocomplexation and plasticization of flexible PEG midblocks offer the PLLA-PEG-PLLA/PDLA-PEG-PDLA blended materials better mechanical and thermomechanical properties. The enantiomeric blends exhibit higher tensile strength, larger elongation-at-break, and better thermal resistance than the corresponding PLLA-PEG-PLLA copolymers.

One-step self-assembly was used to prepare pH-sensitive lappaconitine-loaded low-molecular-weight heparin (LMWH-LA) and to demonstrate that the sulfur group promotes dissolution and has synergistic effect on the analgesic property of lappaconitine (LA). The LMWH-LA was characterized in terms of releasing behavior, pH-sensitivity, analgesic activity and anticoagulation property. The drug loading level of LA in low-molecular-weight heparin (LMWH) reached 24.3% (w/w). The LA, self-assembled in LMWH, released faster in an acidic environment than that in neutral or alkaline environments. Analgesic experiments showed that the LMWH-LA had earlier onset time and longer duration than the LA. Compared with LMWH, the LMWH-LA can reduce clotting time more effectively. These results suggest that the LMWH is a good template and has great potential to achieve synergistic effect of LA. In addition, similar macromolecular structure can be used as a new natural polymeric carrier for loading hydrophobic alkaloids.

In this study, both stretched and annealed polylactide (PLA) films were prepared by a twin-screw extruder with different draw ratios, and the effects of the orientation, crystallization, ambient temperature and humidity on the barrier properties were evaluated. The wide-angle X-ray diffraction results revealed that the crystallinity increase with the increase of draw ratio, and the α'-crystal was produced by uniaxially stretching. Moreover, the α'-crystal was easy to form when the film was annealed at 90°C. Based on the scanning electron microscopy observation, the film surface cracks occurred at a certain draw ratio. Modulated differential scanning calorimetry (MDSC) results showed that the glass-transition temperature and crystallinity increased with the increase of draw ratio. The barrier behavior results showed that, both stretched and annealed PLA films exhibited much better oxygen and water vapor barrier than undrawn PLA at middle draw ratio. Upon further stretching, their barrier ability was reduced. The annealed PLA film had higher barrier ability than that of the stretched PLA film. With regard to the temperature and humidity, the oxygen permeability coefficient increased with the increase of temperature, however, the water vapor permeability coefficient reduced slightly. The oxygen and water vapor permeability coefficient were insensitive to humidity.

pH-sensitive lappaconitine-loaded kappa-carrageenan microparticle (LA-KCG-MP), a degradable, high-load, ionic biopolymer, was prepared using a two-step self-assembly method. Cation exchange resin was selected to degrade kappa-carrageenan (KCG). By investigating the reaction time, temperature, and resin dose, the optimum reaction conditions were determined. Degraded KCG was then easily loaded with a hydrophobic drug, lappaconitine (LA), forming lappaconitine-loaded kappa-carrageenan (LA-KCG) by electrostatic self-assembly. LA-KCG-MP can be prepared by LA-KCG using secondary self-assembly by dialysis subsequently. The loading capacity, release behavior, and pH sensitivity of LA as well as its analgesic properties were determined. Results showed that KCG could be a novel natural polymeric carrier to load a hydrophobic alkaloid, since no synthetic polymer was involved. Furthermore, the loading capacity reached up to 26 % (w/w). Also, LA loaded with KCG was released faster in an acidic environment than that in a neutral environment. The loading capacity and pH sensitivity increased with a decrease in the molecular weight of KCG. In addition, animal analgesic experiments showed that LA-KCG-MP of low molecular weight had earlier onset time and longer duration. These results suggested that KCG of low molecular weight had great potential to achieve the synergistic effect of LA.

Effects of cyanuric acid (CA) on the isothermal and nonisothermal crystallization, morphology, polymorphic crystalline structure, and phase transition on PBA have been investigated systematically by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide-angle X-ray diffraction (WAXD), and Fourier transform infrared (FTIR) spectroscopy. The nonisothermal crystallization temperature increased upon addition of CA. The crystallization kinetics of isothermal crystallization was quantitatively analyzed. CA is an effective nucleating agent for the enhanced nucleation density and decreased spherulite size of PBA. Addition of CA was favorable for the formation of PBA α modification and accelerated the phase transition from the β modification to the α modification. The mechanisms of nucleation, preferential formation of PBA α modification, and accelerated phase transition have also been proposed.

Poly(propylene carbonate) (PPC) was synthesized by the alternating copolymerization of carbon dioxide and propylene oxide (PO). However, during the polymerization, two by-products tended to produce cyclic propylene carbonate (CPC) and a polyether (PE) segment. The excess PO repeat units (PE segment) can easily insert into the PPC backbone and eventually produce the PPC–PO copolymer. The production of CPC and PE segments affected the increase of polymer chain length. In order to investigate the effects of the existence of PE segments, CPC, and molecular weight of fractions on the physical properties of PPC–PO copolymer, a series of fractions with narrow molecular weight distribution were obtained by repeated fractionation. Based on a solvent/non-solvent (chloroform/n-heptane) mixture, an original PPC–PO sample was fractionated into nine fractions with number–average molecular weights (Mn) from 0.34 × 105 to 5.56 × 105 and PE content from 0.4 to 15 mol%. The Mn of PPC–PO fractions decreased with the increas...

Alternating supramolecular multiblock copolymers with hard poly(lactic acid) (PLA) and soft poly(ethylene-co-butylene) (PEB) segments were prepared by terminal functionalization of PLA–PEB–PLA triblock oligomers with the 2-ureido-4[1H]-pyrimidinone (UPy) self-complementary quadruple hydrogen bonding units. Such supramolecular copolymers (SMPs) exhibit the characteristic properties of thermoplastic elastomers. The thermal, morphological, mechanical, shape memory, and self-healing properties of SMPs can be readily modulated by varying the composition, stereostructure, and crystallizability of PLA blocks. The prepared SMPs are shown as transparent and elastic films, while their PLA–PEB–PLA precursors are viscous or brittle solids. Crystallization of isotactic PLA blocks, i.e. poly(L-lactic acid) (PLLA), in SMPs is significantly impeded by the end-caped UPy motifs. The prepared SMPs show a well-defined microphase-separated structure, which varies from cylindrical to lamellar morphology with the increasing fraction of PLA blocks. Compared to the PLA–PEB–PLA precursors, SMPs exhibit improved mechanical strengths, modulus, elongation-at-break, good thermally-induced shape memory and light-triggered self-healing properties. The recovery ratios of SMPs containing atactic poly(D,L-lactic acid) (PDLLA) blocks are nearly 100%. The shape memory and self-healing properties of SMPs can be modulated by the stereostructure of PLA segments and they become worse when the isotactic, crystallizable PLLA segments are presented.

Good barrier packing is particularly important for foods and keeps a suitable atmosphere inside the packages that is condusive to the preservation of the nutrients in food and extend storage time. The development of new technologies has greatly promoted the fabrication of thin film with a certain barrier property and optimizes the internal atmosphere of packages. This chapter focuses on the enhancement of barrier performance of nondegradable and biodegradable plastics as well as their fabrication and application in food packaging. The fabrication techniques include the orientation, coating, nanocompositing, blending, and layer-by-layer (LBL) assemply of nanoparticles based on synthetic and biobased polymers. The major emphasis is on the enhancement of barrier properties to guard against oxygen, carbon dioxide, and water vapor, which is key for food packaging plastics. The fabrication of new high barrier plastics will also be discussed, especially the development and potential application of new biodegradable materials in the food packaging industry.

Glutelins derived from oats were purified and hydrolyzed sequentially using alcalase proteases for production of antioxidant peptides. The antioxidant activities of oat glutelin peptides were evaluated using reducing power methods including hydroxyl and 1,1-diphenyl-2-pycrylhydrazyl (DPPH) radical-scavenging assays. The results demonstrated that oats glutelin peptide D-1a exhibited the highest antioxidant activity compared to the other hydrolysates. D-1a was identified to be His–Tyr–Asn–Ala–Pro–Ala–Leu (784.38 Da) by electrospray ionization mass spectrometry (ESI-MS/MS). Se purificó glutelina derivada de avena e hidrolizada secuencialmente utilizando proteasas de tipo alcalasa para la producción de péptidos antioxidantes. Se evaluó la actividad antioxidante de los péptidos de glutelina de avena utilizando métodos de poder reductor, como por ejemplo ensayos de barrido de radicales hidroxilo y 1,1-difenil-2-picrilhidrazil (DPPH). Los resultados demostraron que los péptidos de glutelina D-1a de la avena exhibieron la mayor actividad antioxidante en comparación con otros hidrolizados. Se identificó D-1a como His-Tyr-Asn-Ala-Pro-Ala-Leu (784,38 Da) mediante espectrometría de masa-ionización por electrospray (ESI-MS/MS).

Poly(propylene carbonate) (PPC) is coated with cellophane (PT) via the intermolecular hydrogen bonds of chitosan (CS) with the both polymers, and their multilayer films are prepared in different weight ratios. The trace presence of chitosan on the surface of PT promotes the combination with PPC layers. After coating, the Young’s modulus and tensile strength of PPC are greatly improved, the storage modulus still keep a high value between ∼0–70°C. The oxygen barrier of PPC is increased at least 580 times, and the multilayer films still keep good water vapor barrier in some degree.

In this study, cellophane (PT) multilayer films were prepared by coating with different thickness of poly(e-caprolactone) (PCL) and chitosan (CH), and its effects on barrier and mechanical properties were evaluated. It was shown that the PCL/PT/PCL and PCL/CH/PT/CH/PCL multilayer films exhibit much better water vapor barrier than PT, and these films still keep the high oxygen barrier. And the barrier properties of multilayer film were improved with the increase of the thickness of coating materials. The Young's modulus and tensile strength of PT multilayer film were slightly decreased, and their elongations at break were increased by coating. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1805–1811, 2013

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It has been investigated the effects of poly(butylene succinate) (PBS) component on the fractionated crystallization, crystalline structure, and spherulite morphology of polymorphic poly(butylene adipate) (PBA) with melting temperature lower than that of PBS in their miscible binary blends. Fractionated crystallization of the PBA component occurs upon blending with PBS depending on the content and crystallization temperature of the PBS component. It is probably related to the distribution of PBA in the PBS matrix. The PBS component suppresses the crystallization of PBA, due to the physical confinement effect of PBS on the PBA component. PBS is favorable for the formation of the PBA α-crystal in the PBS/PBA blends with CPBS ≤ 70%, suggesting that the polymorphism of PBA can be regulated by PBS. The morphology observation reveals that the spherulite growth direction of PBA is controlled by that of PBS. Furthermore, the morphology of PBA is also manipulated by that of PBS rather than the crystallization temperature. The possible mechanism of morphology generation of PBA controlled by PBS has been proposed. The PBS/PBA blend system is an ideal system to study not only on the polymorphism regulation but also on morphology control of biodegradable polymorphic material by polymer blending without losing the biodegradability.

The effects of poly(vinylidene fluoride) (PVDF) component on the crystallization kinetics, crystalline structure, phase transition, and morphology of polymorphic poly(butylene adipate) (PBA) in their miscible PVDF/PBA binary blends have been investigated. The polymorphism of PBA can be regulated upon blending with PVDF. The incorporated PVDF faciliates the formation of PBA α-crystal, which is probably attributed to the thermodynamic and kinetic contributions. From the crystallization kinetics, it was found that a small amount of PVDF acts as a nucleating agent and can accelerate the crystallization of PBA, while a large amount of PVDF hinders the crystallization of PBA due to the confinement effect. In addition, the addition of PVDF greatly accelerates the β- to α-form phase transition of PBA upon annealing the PBA β-form at higher tmeperataure (48 °C). However, the large amount of PVDF decelerates the phase transition to a certain extent. The possible reasons for these phenomena were also proposed.

The nucleation effect of inclusion complex (IC) between poly(3-hydroxybutyrate) (PHB) and alpha-cyclodextrin (α-CD) on the rapid crystallization of a series of bacterial copolyesters poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) with 3HH molar fraction ranging from 7 to 18 mol% was investigated by differential scanning calorimetry (DSC) and a polarized optical microscopy (POM). The results were compared with the effectiveness of PHB particles as a nucleation agent. Both the PHB-IC and the PHB particles enhance the nucleation and crystallization of PHBH, whereas the PHB-IC particles show much more effective nucleation ability than the PHB particles for the crystallization of PHBH. With introduction of PHB-IC, PHBH with 18% 3HH unit can finish crystallization during cooling process from the melt at 10 °C/min, and its crystallinity is greatly increased. The crystallization half-time ( t 1/2 ) of PHBH with 7–18% 3HH units decreases significantly in the presence of PHB-IC. The PHB crystals in the PHB-IC are suggested to favorably nucleate PHBH crystallization with the same crystalline lattice.

Biodegradable polymeric composites were fabricated from poly(butylene succinate) (PBS) and kenaf fiber (KF) by melt mixing technique. The mechanical and dynamic mechanical properties, morphology and crystallization behavior were investigated for PBS/KF composites with different KF contents (0, 10, 20, and 30 wt %). The tensile modulus, storage modulus and the crystallization rate of PBS in the composites were all efficiently enhanced. With the incorporation of 30% KF, the tensile modulus and storage modulus (at 40°C) of the PBS/KF composite were increased by 53 and 154%, respectively, the crystallization temperature in cooling process at 10°C/min from the melt was increased from 76.3 to 87.7°C, and the half-time of PBS/KF composite in isothermal crystallization at 96 and 100°C were reduced to 10.8% and 14.3% of that of the neat PBS, respectively. SEM analysis indicates that the adhesion between PBS and KF needs further improvement. These results signify that KF is efficient in improving the tensile modulus, storage modulus and the crystallization rate of PBS. Hence, this study provides a good option for preparing economical biodegradable composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010