Analysis of mechanical properties of PP⁃CGFR/PP⁃LGFR⁃integrated over⁃molding products

doi:10.19491/j.issn.1001-9278.2025.05.001

Abstract

Abstract:

Glass⁃fiber⁃reinforced polypropylene was used to prepare integrated over⁃molding products. The significant factors affecting tensile strength and bending strength of the molded products were investigated by an orthogonal experiment， and the influence of process parameters on their mechanical properties was analyzed. Furthermore， the tensile and bending failure modes of the molded products under different process parameters were discussed， the microscopic morphology of their failure section was observed， and the correlations between their molding process and microstructure and mechanical properties were established. The results indicated that the significant factors affecting the tensile strength included the preheating temperature， holding pressure， and mold temperature. The significant factors affecting the bending strength were the preheating temperature， holding pressure， and melt temperature. The bonding strength between organic sheets and injection molding materials and the degree of fiber⁃resin bonding of the organic sheet were the main factors affecting the mechanical properties of the molded products.

Key words: polypropylene, glass fiber, integrated over?molding, mechanical property, microstructure

CLC Number:

TQ325.1⁺4

WU Xiran, JIA Zhixin, LIU Lijun, LI Jiqiang, ZHAO Chuantao, CHEN Bojie. Analysis of mechanical properties of PP⁃CGFR/PP⁃LGFR⁃integrated over⁃molding products[J]. China Plastics, 2025, 39(5): 1-8.

Figures/Tables 14

Fig.1. Sample preparation process of the integrated over⁃molding process

水平	因素
水平	A/℃	B/℃	C/℃	D/%	E/bar
1	130	40	220	35	30
2	150	50	230	40	40
3	170	60	240	45	50
4	200	70	250	50	60
5	220	80	260	55	70

Tab.1. Factor level of the orthogonal tests

Fig.2. Size of the samples

实验编号	工艺参数组合	$σ t$ /MPa	$σ f$ /MPa	$S t$	$S f$
1	A₁B₁C₁D₁E₁	132.03	165.40	16.74	21.41
2	A₄B₁C₂D₅E₅	196.62	268.52	22.75	26.32
3	A₅B₁C₄D₃E₃	173.77	282.53	19.21	38.12
4	A₃B₁C₅D₂E₂	157.41	198.33	22.54	27.14
5	A₂B₁C₃D₄E₄	134.51	169.70	14.32	22.12
6	A₅B₂C₂D₂E₄	181.30	251.27	28.97	26.10
7	A₄B₂C₅D₄E₁	139.19	253.25	26.12	46.12
8	A₂B₂C₁D₃E₅	158.99	172.04	15.21	32.12
9	A₁B₂C₄D₅E₂	161.18	177.14	29.41	43.21
10	A₃B₂C₃D₁E₃	132.30	166.28	22.12	26.78
11	A₁B₃C₂D₄E₃	167.19	172.06	20.41	33.12
12	A₅B₃C₅D₁E₅	200.13	236.47	31.54	19.54
13	A₄B₃C₃D₃E₂	163.13	212.62	23.58	21.12
14	A₂B₃C₄D₂E₁	146.11	200.98	38.62	31.24
15	A₃B₃C₁D₅E₄	165.59	192.28	26.94	25.98
16	A₁B₄C₅D₃E₄	150.24	162.45	18.42	13.12
17	A₅B₄C₃D₅E₁	163.09	238.15	24.65	24.12
18	A₃B₄C₄D₄E₅	168.75	184.62	19.54	36.12
19	A₄B₄C₁D₂E₃	170.67	279.34	32.41	47.81
20	A₂B₄C₂D₁E₂	144.54	162.95	23.35	24.35
21	A₂B₅C₅D₅E₃	173.37	220.12	42.32	18.45
22	A₃B₅C₂D₃E₁	161.23	217.08	13.54	11.02
23	A₁B₅C₃D₂E₅	165.44	160.27	23.57	20.13
24	A₄B₅C₄D₁E₄	176.29	272.13	24.21	21.86
25	A₅B₅C₁D₄E₂	201.30	227.64	27.64	29.64

实验编号	工艺参数组合	$σ t$ /MPa	$σ f$ /MPa	$S t$	$S f$
1	A₁B₁C₁D₁E₁	132.03	165.40	16.74	21.41
2	A₄B₁C₂D₅E₅	196.62	268.52	22.75	26.32
3	A₅B₁C₄D₃E₃	173.77	282.53	19.21	38.12
4	A₃B₁C₅D₂E₂	157.41	198.33	22.54	27.14
5	A₂B₁C₃D₄E₄	134.51	169.70	14.32	22.12
6	A₅B₂C₂D₂E₄	181.30	251.27	28.97	26.10
7	A₄B₂C₅D₄E₁	139.19	253.25	26.12	46.12
8	A₂B₂C₁D₃E₅	158.99	172.04	15.21	32.12
9	A₁B₂C₄D₅E₂	161.18	177.14	29.41	43.21
10	A₃B₂C₃D₁E₃	132.30	166.28	22.12	26.78
11	A₁B₃C₂D₄E₃	167.19	172.06	20.41	33.12
12	A₅B₃C₅D₁E₅	200.13	236.47	31.54	19.54
13	A₄B₃C₃D₃E₂	163.13	212.62	23.58	21.12
14	A₂B₃C₄D₂E₁	146.11	200.98	38.62	31.24
15	A₃B₃C₁D₅E₄	165.59	192.28	26.94	25.98
16	A₁B₄C₅D₃E₄	150.24	162.45	18.42	13.12
17	A₅B₄C₃D₅E₁	163.09	238.15	24.65	24.12
18	A₃B₄C₄D₄E₅	168.75	184.62	19.54	36.12
19	A₄B₄C₁D₂E₃	170.67	279.34	32.41	47.81
20	A₂B₄C₂D₁E₂	144.54	162.95	23.35	24.35
21	A₂B₅C₅D₅E₃	173.37	220.12	42.32	18.45
22	A₃B₅C₂D₃E₁	161.23	217.08	13.54	11.02
23	A₁B₅C₃D₂E₅	165.44	160.27	23.57	20.13
24	A₄B₅C₄D₁E₄	176.29	272.13	24.21	21.86
25	A₅B₅C₁D₄E₂	201.30	227.64	27.64	29.64

Tab.2. Orthogonal test results of mechanical properties of the PP⁃CGFR/PP⁃LGFR products

因素	拉伸强度			弯曲强度
因素	自由度	均方	显著性	自由度	均方	显著性
误差	4	52.755	—	4	86.101	—
预热温度	4	878.916	0.009	4	7 962.841	0
模具温度	4	357.496	0.045	4	304.300	0.124
熔体温度	4	240.080	0.086	4	811.015	0.026
注射速度	4	149.333	0.169	4	388.325	0.087
保压压力	4	559.510	0.021	4	571.796	0.047

Tab.3. Orthogonal experimental ANOVA of tensile properties of the PP⁃CGFR/PP⁃LGFR products

Fig.3. Variation trend of the tensile and bending strength with process parameters

Fig.4. Stress⁃strain curves of the tensile samples

Fig.5. Mesoscopic morphology of the sample A4 tensile failure

Fig.6. Mesoscopic morphology of the sample A24 tensile failure

Fig.7. Comparison of failure cross⁃section morphology of the tensile samples

Fig.8. Stress⁃strain curves of the bending samples

Fig.9. Mesoscopic and microscopic morphology of the sample A10 bending failure

Fig.10. Mesoscopic and microscopic morphology of the sample A2 bending failure

Fig.11. Comparison of failure cross⁃section morphology of the bending samples

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