# Maleic Anhydride-Grafted Isotactic Polybutene-1 and Modified Polyamide 6
## Materials and Methods
### Characterizations  
The purified samples were hot pressed into thin films with thickness of 0.1 mm at 160 \({}^{\circ}\)C under 10 MPa for 5 min using the 600 T plate press (Huzhou Dongfang Machinery Co., Ltd., Huzhou, China).  
The samples were analyzed by FTIR spectroscopy (Vertex70, Bruker, Germany). The appearance of absorption peak at 1780 cm\({}^{-1}\) (corresponding to the characteristic absorption peak of the carbonyl groups of MAH) and 2720 cm\({}^{-1}\) (the characteristic absorption peak of iPB-1 skeleton) [21] were integrated, and the ratio of the peak area (RaMAH = \(A_{\rm 1780 cm^{-1}}/A_{\rm 2720 cm^{-1}}\)) was the relative grafting degree of MAH. Based on the acid-base titration [16] and infrared results, a calibration curve was constructed to obtain the formula Gd% = 0.3754\(A_{\rm 1780 cm^{-1}}/A_{\rm 2720 cm^{-1}}\), which can be used for calculating absolute grafting degree (Gd) of iPB-g-MAH [18].  
The samples were tested through MFR (190 \({}^{\circ}\)C, 2.16 kg) using GT-7100-MI type equipment (GOTECH, Taiwan), according to ISO 1133-1-2011.  
The hot-pressed sample films, left at room temperature for one week, were analyzed by a contact angle measuring instrument (DH-HV1351 UM type, Shanghai Zhongchen Digital Technology Equipment Co., Ltd., Shanghai, China), using distilled water as a measuring liquid [22].  
The isothermal crystallization process of the samples was observed by professional polarizing microscope (OLYMPUS BX5, OLYMPUS, Tokyo, Japan). The sample was heated from room temperature to 160 \({}^{\circ}\)C at a rate of 10 \({}^{\circ}\)C/min, then, maintained for 10 min, and cooled down to 85 \({}^{\circ}\)C at a rate of 60 \({}^{\circ}\)C/min. The isothermal crystallization process occurred at 85 \({}^{\circ}\)C, and the crystal form was recorded per minute.  
The Gd of iPB-g-MAH prepared in a double screw extruder (SHJ-30, Nanjing JieEnte Electromechanical Co., Ltd., Nanjing, China) was 1.5%. iPB, iPB-g-MAH (Gd = 1.5%) and PA6 were mixed in a high-speed mixer and uniformly mixed and extruded for granules. The injection molding machine (F2v130, Donghua Machinery Co., Ltd., Dongguan, China) was used to inject the extrudates into standard samples for performance testing. Tensile strength and elongation at break were measured according to ISO 527-1993. The test specimens were type I. Notched impact strength were tested according to ISO 179-1993. Shore D hardness were tested according to ISO 7619-1986. Vicat softening point were tested according to ISO 306-1994.  
The thermal analyses of PA6/iPB-g-MAH and PA6/iPB were carried out with a differential scanning calorimeter (model NETZSCH-204, NETZSCH, Selb, Germany). The sample was heated from room temperature to 260 \({}^{\circ}\)C, then cooled down to room temperature, then heated to 260 \({}^{\circ}\)C at a rate of 10 \({}^{\circ}\)C/min, under constant nitrogen flow. Temperature and heat flow scales were calibrated using a standard indium sample.  
Scanning electron microscope (JSM-7500F, Japan Electronics Co., Ltd., Tokyo, Japan) was used to observe the morphology of impact sections of different samples.