STUDY OF THE PROPERTIES OF POLYMER COMPOSITIONS AND PARTS BASED ON THEM, CREATED FROM POLYPROPYLENE AND FIBROUS FILLERS

АННОТАЦИЯ

В работе представлены результаты исследования свойств композиционных материалов на основе полипропилена, армированных волокнистыми наполнителями (стекловолокно), разработанных для производства автомобильных деталей АО «UzAuto Motors». Определены основные физико-механические и термостойкие характеристики полученных компаундов и проведено их сопоставление с требованиями стандартов General Motors (GMW). Экспериментальные данные показали, что созданные композиции полностью соответствуют требованиям к прочности, ударной вязкости и термостойкости, а также обеспечивают высокое качество поверхности изделий. Использование отечественного сополимера полипропилена производства СП ООО «Uz-Kor Gas Chemical» позволяет снизить себестоимость и степень импортозависимости при сохранении эксплуатационных свойств на уровне зарубежных аналогов.

ABSTRACT

The study investigates the properties of polypropylene-based composite materials reinforced with fibrous fillers (glass fibers), developed for automotive components produced by JSC “UzAuto Motors.” The mechanical and thermal properties of the developed compounds were analyzed and compared with General Motors (GMW) standards. The results confirmed that the domestically produced polypropylene-based composites fully meet the requirements for strength, impact resistance, and heat deflection temperature, while maintaining excellent surface quality. Utilizing locally produced polypropylene copolymer (JV LLC “Uz-Kor Gas Chemical”) reduces costs and import dependence, ensuring competitive product performance.

Ключевые слова: полипропилен, стекловолокно, компаунд, механические свойства, термостойкость.

Keywords: polypropylene, fiberglass, compound, mechanical properties, heat resistance.

Introduction. Modern automotive manufacturing requires polymer composites with high heat resistance, mechanical strength, durability against aging, and chemical stability. At the same time, localization of raw materials and cost reduction remain essential industrial objectives. This research focuses on the development and study of polypropylene-based composites reinforced with glass fibers, intended for the production of automotive parts for Chevrolet Onix and Tracker vehicles manufactured by JSC “UzAuto Motors.”

Materials and Methods. The polymer matrix used in this study was a polypropylene copolymer produced by JV LLC “Uz-Kor Gas Chemical.” The glass fiber content ranged from 20 to 40 wt%. All tests were conducted according to international ISO and General Motors (GMW) standards. For each property, the mean value (M), standard deviation (σ), and number of samples (n = 5) were determined.

Results. Previous studies [1–3] reported the use of polypropylene-based polymer compositions, produced by JV LLC “Uz-Kor Gas Chemical,” with powder-type fillers such as talc and, to a lesser extent, chalk, obtained from local and Afghan deposits. Based on these formulations, several plastic automotive components were successfully developed and implemented in production. At this stage, the focus was shifted toward developing polypropylene compounds with enhanced thermal and mechanical performance, using low-cost, widely available raw materials. Fibrous materials have been identified as the most promising fillers for this purpose. Proper selection of such reinforcements allows the use of cost-effective base polymers, including polyethylene and polypropylene. Numerous studies confirm the feasibility of developing such fiber-reinforced composites [4,5]. The developed compositions — CF352M-UZ, CF892M-UZ, CT452T-UZ, and CF257M-UZ — fully met the requirements of standards GMW16607P, GMW16892, GMW15702, and GMW16606, respectively. An increase in glass fiber content led to a significant rise in the modulus of elasticity, from 3.8 to 8.6 GPa. All samples demonstrated high impact strength even at –30 °C and good thermal aging resistance. Testing of molded automotive parts (fan shrouds, holders, mirror housings, and structural supports) confirmed compliance with appearance, flammability, fogging, odor, and chemical resistance requirements.

Table 1.

Correlation between developed compositions and GMW grades, and their application in Chevrolet Onix and Tracker models

Earlier-developed compositions were manufactured using the domestic polypropylene copolymer from JV LLC “Uz-Kor Gas Chemical,” with the goal of substituting imported polymers. The performance characteristics of the obtained compounds compared to the GMW requirements are summarized in Tables 2–5. The results demonstrate full compliance of the developed grades with the target specifications.

Table 2.

Laboratory test results for CF352M-UZ grade

Table 3.

Laboratory test results for CF892M-UZ grade

Table 4.

Laboratory test results for CT452T-UZ grade.

Table 5.

Laboratory test results for CF257M-UZ grade

Table 6.

Summary of all polypropylene-based compositions compared with GMW requirements

The experimental results showed that all parameters of the created polypropylene composite met the required specifications. Subsequently, these composites were used to manufacture parts, which were produced in industrial injection molding machines under standard conditions and subsequently subjected to laboratory testing. We previously conducted similar studies on plastic automotive parts made from polypropylene produced by “Uz Kor Gaz Chemical” JV LLC, using talc powder as a filler [5].

Table 7 presents the conditions for producing parts in injection molding machines.

Table 7.

Test conditions

The molding regime for the domestic compounds did not differ from that used for imported materials. Performance testing of molded components (Tables 8–11) demonstrated compliance with visual, mechanical, and environmental standards.

Table 8.

Test results of part “Fan shrouds, bracket”

Table 9.

Test results of part “Clips, holders”

Table 10.

Test results of part “Mirror housing base”

Table 11.

Test results of part “Trim mounting parts”

All tested materials were cast without defects.

Thus, based on the results of the work, it can be concluded that both the developed polypropylene composite samples and the parts molded using them meet the product requirements set by “UzAuto Motors” JSC.

Data analysis shows:

1. Strength and Tensile Modulus. As the glass fiber content increases, the modulus of elasticity increases:

for CF352M-UZ (PP GF20) – 3817 ± 95 МPа,

for CF892M-UZ (PP GF30) – 5870 ± 110 МPа,

for CT452T-UZ (PP GF40) – 8650 ± 130 МPа,

for CF257M-UZ (PP GF25+M15) – 6850 ± 120 МPа.

Thus, the pattern of polypropylene reinforcement is confirmed: an increase in the glass fiber content leads to an increase in the modulus of elasticity from ~3.8 thousand MPa (20% GF) to ~8.6 thousand MPa (40% GF).

2. Impact Strength. Despite higher rigidity, all compounds maintained impact resistance above the minimum requirements, including at –30 °C, ensuring reliability under low-temperature operating conditions.

3. Thermal Resistance. The heat deflection temperature exceeds GMW standards, making the materials suitable for under-hood applications.

4. Surface and Aesthetic Properties.  Tests on molded components confirmed (table 7–11) excellent surface quality, oxidation resistance, acceptable odor and fogging, and compliance with flammability requirements.

Thus, the materials not only meet the requirements of the standards, but in some cases exceed them, which allows them to be considered as a full-fledged replacement for imported analogues.

Conclusion:

- The polypropylene-based composites reinforced with glass fibers, developed using domestic copolymer, fully comply with General Motors standards.

- Automotive components molded from these materials meet operational requirements in terms of strength, appearance, and durability.

- The use of locally produced raw materials reduces production costs, minimizes import dependence, and contributes to the localization of polymer materials in Uzbekistan’s automotive industry.

References:

1. Aykhodjaev B.B., Adilov R.I., Usmanov I.T. Regulation of properties of polypropylene composites with fillers. Chemistry and Chemical Technology, 2022, No. 3, pp. 28–33.
2. Adilov R., Aykhodjaev B., Rajabov R. Comparative analysis of polypropylene composites with fibrous fillers for automotive parts. European International Journal of Multidisciplinary Research and Management Studies, 2023, Vol. 3, Issue 6, pp. 33–39.
3. Kurbanbekov F., Aykhodjaev B., Rajabov R. Development of glass fiber reinforced polypropylene compounds for automotive applications. Proceedings of the International Conference “Innovative Approaches in Polymer Engineering”, Tashkent, 2022.
4. Bhattacharya S., Kumar A. Polypropylene Composites: Mechanical Properties and Applications. Elsevier, 2019.
5. Brandrup J., Immergut E. Polymer Handbook, 5th Edition, Wiley, 2018.