The natural clam shell (CS) has a unique CaCO3‐proteoglycan structure which can be beneficial in improving the strength of materials as a result of the stiff CaCO3 content present in it. Moreover, the existence of active groups such as hydroxyl groups, carboxyl groups, and amino groups in CS can make it possible to form chemical bonds with some functional groups in other materials. In this work, CS which is mostly regarded as waste was utilized to prepare compatible composites via melting process with biodegradable polycaprolactone (PCL). Addition of 15 wt % of polyurethane prepolymer as a compatibilizer to a designed weight ratio of 1 to 1 of CS powder and PCL increased the elongation at break of the composite from 9.3 to 536.5%, and also improved the tensile strength from 14.9 to 18.9 MPa. Particularly important was that scanning electron microscopy investigation revealed that the adhesion between the CS and PCL improved significantly as the content of the compatibilizer was increased. This work shows that CS has great potential applications in the area of compatible composites and could serve as an alternative material for reinforcement in polymer composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48768.

As is well known, poor interfacial interactions between hydrophilic corn starch (CS) and hydrophobic thermoplastic matrices have been an obstacle in application of the quality biomass material like CS. The addition of compatibilizers is an effective method to improve the interface interaction. In this work, a special interficial structure using polyurethane crosslinked layer as compatible interface is designed and compatibilizers with different NCO functionality are also applied. The purpose of this work is to investigate the effects of compatibilizers with different NCO functionality (f, f = 0, 1, 2, 3) on the compatibility of corn starch‐polycaprolactone (CS‐PCL) composites. Subsequently, various CS‐PCL composites are prepared using compatiblizers with different NCO functionality (f = 0, 1, 2, 3) via melting process. The structural analysis, mechanical properties, and water absorption capability as well as the thermal stability of the composites reveal that the properties of the composites are only enhanced significantly when the NCO functionality is no less than 2. In short, when f ≥ 2, a crosslinked layer could be formed at the interface of the composite to afford a compatible CS‐PCL composite.

In this work, the effects of particle size and content of clam shell powder (CSP) on the mechanical properties and microstructure of clam shell powder‐polycaprolactone (CSP‐PCL) composites were studied. Accordingly, shell powder with particle size of 50, 100, 200, and 400 meshes, and CSP content of 30, 40, 50, and 60 wt%, respectively, were utilized to prepare CSP‐PCL composites. The interface structure and properties of CSP‐PCL composites were investigated by infrared spectroscopy (IR), X‐Ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis (TGA), and tensile tests. The results showed that the tensile properties of the composite materials correlated with the particle size and content of the filler. For instance, the smaller the particle size of CSP (400 meshes), the better the tensile properties of the composite. What is more, the tensile properties of the composites were negatively affected by the amount of CSP content. In terms of microstructure, shell powder particles could disperse uniformly in the PCL matrix, and the CSP‐PCL composites with polyurethane prepolymer as compatibilizer gave a better compatibility.

Castor oil (CO) is an environmentally friendly renewable green resource and ideal alternative to petroleum resources. The preparation of high strength and high toughness castor oil-based polyurethane prepolymer (COPU) composites has significant applications such as supporting material and engineering plastic sheet. In this study, unmodified clam shell powder (CSP) with a unique CaCO 3-proteoglycan structure was used as a filler to prepare compatible reinforced COPU composite materials. Investigation of the mechanical properties revealed that the elastic modulus of the composite COPU reinforced with 50 wt% of CSP had increased to 5859.0 ± 8.4 MPa representing 187.77% to obtain stiffer and stronger material over pure COPU (2036.6 ± 196.9 MPa). Moreover, the scanning electron microscopy, thermogravimetric analysis and contact angle results demonstrated that the reinforced COPU composites have better compatibility, thermal stability, and water resistance than pure COPU. This work will promote the application prospects of CO-based polyurethane.